title:
Non-coplanar magnetism, topological density wave order and emergent
  symmetry at half-integer filling of moir\'{e} Chern bands

abstract:
  We study the impact of Coulomb interactions at half-integer filling of the
moir\'e Chern bands of twisted double-bilayer graphene and twisted mono-bilayer
graphene, using unbiased exact diagonalization complemented by unrestricted
Hartree-Fock calculations. For small intra-sublattice tunneling, $w_{AA}$, a
non-coplanar magnetic state is found which has the same symmetries as the
tetrahedral antiferromagnet of the triangular moir\'e lattice and can be
thought of as a skyrmion lattice commensurate with the moir\'e scale. The
antiferromagnetic order competes with a set of ferromagnetic, topological
charge density waves, which are favored for larger $w_{AA}$ and are associated
with an approximate emergent O(3) symmetry, `rotating' the different charge
density wave states into each other. Direct comparison with exact
diagonalization reveals that the ordered phases are accurately described within
the unrestricted Hartree-Fock approximation. Exhibiting a finite charge gap and
Chern number $C=\pm1$, the formation of charge density wave order which is
intimately connected to a skyrmion lattice phase is consistent with recent
experiments on these systems.


title:
The Next Generation Virgo Cluster Survey. XXXIII. Stellar Population
  Gradients in the Virgo Cluster Core Globular Cluster System

abstract:
  We present a study of the stellar populations of globular clusters (GCs) in
the Virgo Cluster core with a homogeneous spectroscopic catalog of 692 GCs
within a major axis distance $R_{\rm maj} = $ 840 kpc from M87. We investigate
radial and azimuthal variations in the mean age, total metallicity, [Fe/H], and
$\alpha$-element abundance, of blue (metal-poor) and red (metal-rich) GCs using
their co-added spectra. We find that the blue GCs have a steep radial gradient
in [Z/H] within $R_{\rm maj} =$ 165 kpc, with roughly equal contributions from
[Fe/H] and [$\alpha$/Fe], and flat gradients beyond. By contrast, the red GCs
show a much shallower gradient in [Z/H], which is entirely driven by [Fe/H]. We
use GC-tagged Illustris simulations to demonstrate an accretion scenario where
more massive satellites (with more metal- and $\alpha$-rich GCs) sink further
into the central galaxy than less massive ones, and where the gradient
flattening occurs because of the low GC occupation fraction of low-mass dwarfs
disrupted at larger distances. The dense environment around M87 may also cause
the steep [$\alpha$/Fe] gradient of the blue GCs, mirroring what is seen in the
dwarf galaxy population. The progenitors of red GCs have a narrower mass range
than those of blue GCs, which makes their gradients shallower. We also explore
spatial inhomogeneity in GC abundances, finding that the red GCs to the
northwest of M87 are slightly more metal-rich. Future observations of GC
stellar population gradients will be useful diagnostics of halo merger
histories.


title: Quantum-critical electrodynamics of Luttinger fermions

abstract:
  We study the quantum electrodynamics of Luttinger fermions with quadratic
band-crossing dispersion in three dimensions. The model can be viewed as the
low-energy effective theory of a putative $U(1)$ quantum spin liquid with
fermionic Luttinger spinons, or as an extension of the
Luttinger-Abrikosov-Beneslavskii (LAB) model that accounts for transverse gauge
fluctuations with finite photon velocity. Aided by a renormalization group
analysis below four dimensions, we elucidate the presence and stability of
quantum critical phenomena in this model. We find that the non-Fermi liquid LAB
phase is stable against gauge fluctuations, and can thus also be viewed as a
$U(1)$ spin liquid with gapless Luttinger spinons. We discover a multicritical
point with Lifshitz scaling that corresponds to a time-reversal
symmetry-breaking quantum phase transition from the LAB state to a chiral spin
liquid with spinon Landau levels and birefringent emergent photons. This
multicritical point is characterized by a finite fermion-photon coupling in the
infrared and can be viewed as a fermionic analog of the Rokhsar-Kivelson point
in three-dimensional quantum dimer models.


title:
Fractional disclination charge and discrete shift in the Hofstadter
  butterfly

abstract:
  In the presence of crystalline symmetries, topological phases of matter
acquire a host of invariants leading to non-trivial quantized responses. Here
we study a particular invariant, the discrete shift $\mathscr{S}$, for the
square lattice Hofstadter model of free fermions. $\mathscr{S}$ is associated
with a $\mathbb{Z}_M$ classification in the presence of $M$-fold rotational
symmetry and charge conservation. $\mathscr{S}$ gives quantized contributions
to (i) the fractional charge bound to a lattice disclination, and (ii) the
angular momentum of the ground state with an additional, symmetrically inserted
magnetic flux. $\mathscr{S}$ forms its own `Hofstadter butterfly', which we
numerically compute, refining the usual phase diagram of the Hofstadter model.
We propose an empirical formula for $\mathscr{S}$ in terms of density and flux
per plaquette for the Hofstadter bands, and we derive a number of general
constraints. We show that bands with the same Chern number may have different
values of $\mathscr{S}$, although odd and even Chern number bands always have
half-integer and integer values of $\mathscr{S}$ respectively.


title:
BASS XXV: DR2 Broad-line Based Black Hole Mass Estimates and Biases from
  Obscuration

abstract:
  We present measurements of broad emission lines and virial estimates of
supermassive black hole masses ($M_{BH}$) for a large sample of ultra-hard
X-ray selected active galactic nuclei (AGNs) as part of the second data release
of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes $M_{BH}$
estimates for a total 689 AGNs, determined from the H$\alpha$, H$\beta$,
$MgII\lambda2798$, and/or $CIV\lambda1549$ broad emission lines. The core
sample includes a total of 512 AGNs drawn from the 70-month Swift/BAT all-sky
catalog. We also provide measurements for 177 additional AGNs that are drawn
from deeper Swift/BAT survey data. We study the links between $M_{BH}$
estimates and line-of-sight obscuration measured from X-ray spectral analysis.
We find that broad H$\alpha$ emission lines in obscured AGNs ($\log (N_{\rm
H}/{\rm cm}^{-2})> 22.0$) are on average a factor of $8.0_{-2.4}^{+4.1}$
weaker, relative to ultra-hard X-ray emission, and about $35_{-12}^{~+7}$\%
narrower than in unobscured sources (i.e., $\log (N_{\rm H}/{\rm cm}^{-2}) <
21.5$). This indicates that the innermost part of the broad-line region is
preferentially absorbed. Consequently, current single-epoch $M_{BH}$
prescriptions result in severely underestimated ($>$1 dex) masses for Type 1.9
sources (AGNs with broad H$\alpha$ but no broad H$\beta$) and/or sources with
$\log (N_{\rm H}/{\rm cm}^{-2}) > 22.0$. We provide simple multiplicative
corrections for the observed luminosity and width of the broad H$\alpha$
component ($L[{\rm b}{\rm H}\alpha]$ and FWHM[bH$\alpha$]) in such sources to
account for this effect, and to (partially) remedy $M_{BH}$ estimates for Type
1.9 objects. As key ingredient of BASS/DR2, our work provides the community
with the data needed to further study powerful AGNs in the low-redshift
Universe.


title:
Fermionic approach to variational quantum simulation of Kitaev spin
  models

abstract:
  We use the variational quantum eigensolver (VQE) to simulate Kitaev spin
models with and without integrability breaking perturbations, focusing in
particular on the honeycomb and square-octagon lattices. These models are well
known for being exactly solvable in a certain parameter regime via a mapping to
free fermions. We use classical simulations to explore a novel variational
ansatz that takes advantage of this fermionic representation and is capable of
expressing the exact ground state in the solvable limit. We also demonstrate
that this ansatz can be extended beyond this limit to provide excellent
accuracy when compared to other VQE approaches. In certain cases, this
fermionic representation is advantageous because it reduces by a factor of two
the number of qubits required to perform the simulation. We also comment on the
implications of our results for simulating non-Abelian anyons on quantum
computers.


title: Asymmetric transverse momentum broadening in an inhomogeneous medium

abstract:
  Gradient jet tomography in high-energy heavy-ion collisions utilizes the
asymmetric transverse momentum broadening of a propagating parton in an
inhomogeneous medium. Such broadening is studied within a path integral
description of the evolution of the Wigner distribution for a propagating
parton in medium. Going beyond the eikonal approximation of multiple
scattering, the evolution operator in the transverse direction can be expressed
as the functional integration over all classical trajectories of a massive
particle with the light-cone momentum $\omega$ as its mass. With a dipole
approximation of the Wilson line correlation function, evolution with the
light-cone time $t$ is determined by the jet transport coefficient $\hat q$
that can vary with space and time. In a uniform medium with a constant $\hat
q_0$, the analytical solution to the Wigner distribution becomes a typical
drifted Gaussian in both transverse momentum and coordinate with the diffusion
width $\sqrt{\hat q_0t}$ and $\sqrt{\hat q_0t^3/3\omega^2}$, respectively. In
the case of a simple Gaussian-like transverse inhomogeneity with a spatial
width $\sigma$ on top of a uniform medium, the final asymmetrical momentum
distribution can be calculated semi-analytically. The transverse asymmetry
defined for jet gradient tomography that characterizes the asymmetrical
distribution is found to linearly correlate with the initial transverse
position of the propagating parton within the domain of the inhomogeneity. It
decreases with the parton energy $\omega$, increases with the propagation time
initially and saturates when the diffusion distance is much larger than the
size of the inhomogeneity or $t^3\gg 3\omega^2\sigma^2/\hat q_0$. The
transverse momentum broadening due to the inhomogeneity also saturates at late
time in contrast to the continued increase with time if the drifted diffusion
in space is ignored.


title: Thermodynamic ensembles with cosmological horizons

abstract:
  The entropy of a de Sitter horizon was derived long ago by Gibbons and
Hawking via a gravitational partition function. Since there is no boundary at
which to define the temperature or energy of the ensemble, the statistical
foundation of their approach has remained obscure. To place the statistical
ensemble on a firm footing we introduce an artificial "York boundary", with
either canonical or microcanonical boundary conditions, as has been done
previously for black hole ensembles. The partition function and the density of
states are expressed as integrals over paths in the constrained, spherically
reduced phase space of pure 3+1 dimensional gravity with a positive
cosmological constant. Issues related to the domain and contour of integration
are analyzed, and the adopted choices for those are justified as far as
possible. The canonical ensemble includes a patch of spacetime without horizon,
as well as configurations containing a black hole or a cosmological horizon. We
study thermodynamic phases and (in)stability, and discuss an evolving reservoir
model that can stabilize the cosmological horizon in the canonical ensemble.
Finally, we explain how the Gibbons-Hawking partition function on the 4-sphere
can be derived as a limit of well-defined thermodynamic ensembles and, from
this viewpoint, why it computes the dimension of the Hilbert space of states
within a cosmological horizon.


title: Dynamical characterization of galaxies up to $z \sim 7$

abstract:
  The characterization of the dynamical state of galaxies up to z~7 is crucial
for constraining the mechanisms driving the mass assembly in the early
Universe. However, it is unclear whether the data quality of current and future
observations is sufficient to perform a solid dynamical analysis. This paper
defines the angular resolution and S/N required for a robust characterization
of the dynamical state of galaxies up to the EoR. The final aim is to help
design spatially-resolved surveys targeting emission lines of primeval
galaxies. We investigate the [CII]-158um emission from z~6-7 LBGs from the
SERRA cosmological simulation, covering a range of dynamical states: from disks
to major mergers. We create ALMA mock observations with various data quality
and apply the kinematic classification methods used in the literature. These
tests allow us to quantify the performances of such methods as a function of
angular resolution and S/N. We find that barely-resolved observations do not
allow the correct dynamical characterization of a galaxy, resulting in the
misclassification of all disks in our sample. However, even when using
spatially-resolved observations with data quality typical of high-z galaxies,
the standard kinematic classification methods, based on the analysis of the
moment maps, fail to distinguish a merger from a disk. The high angular
resolution and S/N needed to apply these standard methods successfully can be
achieved with current data only for a handful of bright galaxies. We propose a
new classification method, called PVsplit, that quantifies the asymmetries and
morphological features in position-velocity diagrams using three empirical
parameters. We test PVsplit on our mock data concluding that it can predict
whether a galaxy is a disk or a merger provided that S/N $\gtrsim10$, and the
major axis is covered by $\gtrsim3$ independent resolution elements.


title: Entanglement in interacting quenched Quantum Field Theory

abstract:
  In this work, we explore the effects of a quantum quench on the entanglement
entropy for a system of scalar field having $\phi^4$ interaction. We use the
method of invariant operator representation for the computation of the ground
state of coupled Hamiltonian having $\lambda\phi^4$ perturbation. We give the
analytical expressions for the total and reduced density matrix of the system
having non-Gaussian, quartic interaction terms. Using this reduced density
matrix, we show the analytical calculation of two entanglement measures viz.,
Von Neumann entanglement entropy using replica trick and Renyi entanglement
entropy. Further, we give a numerical estimate of these entanglement measures
with respect to the dimensionless parameter $(t/\delta t$) and show its
behaviour in the three regimes, i.e; late time behaviour, around the quench
point and the early time behaviour. We comment on the variation of these
entanglement measures for different orders of coupling strength. The variation
of Renyi entropy of different orders has also been discussed.

categories: hep-th cond-mat.stat-mech gr-qc hep-ph quant-ph


title:
Exploring the landscape of (anti-) de Sitter and Minkowski solutions:
  group manifolds, stability and scale separation

abstract:
  We classified in arXiv:2201.04152 certain 10d supergravity solutions with a
4d de Sitter, Minkowski or anti-de Sitter spacetime. We then found new
solutions in previously unexplored classes. In this paper we study their
properties, compare them to swampland conjectures, and make new observations.
  Using new numerical tools, we first identify all Lie algebras underlying the
6d group manifolds, allowing us to discuss their compactness. We then
investigate scale separation, and prove related no-go theorems. Last but not
least, we automatize and analyze the stability of all solutions. This leads us
to propose the Massless Minkowski Conjecture, claiming the systematic presence
of a 4d flat direction.


title: Current Algebra Approach to 2d Chiral Metals

abstract:
  We reinterpret Balents and Fisher's free 2d chiral metal [Phys. Rev. Lett.
76, 2782 (1996)] as a chiral $U(N)$ Wess-Zumino-Witten model at level $k = 1$.
Here, the $U(N)$ symmetry relates the $N \rightarrow \infty$ low-energy
excitations about the chiral Fermi surface. We obtain non-Fermi liquid
generalizations of the free chiral metal that maintain the $U(N)$ symmetry of
the $k=1$ theory by taking the level to be a positive integer $k>1$. We
calculate two-point correlation functions of the $U(1)$ number density and
current operators in these theories for general $k$. We find $k$ to provide an
overall rescaling of the amplitude of these correlation functions. This
construction illustrates the ersatz Fermi liquid proposal of Else, Thorgren,
and Senthil [Phys. Rev. X 11, 021005 (2021)].


title: Anomalous fractal scaling in two-dimensional electric networks

abstract:
  We observe a profound deviation from logarithmic scaling for the impedance of
a two-dimensional LC circuit network. We find this anomalous impedance
contribution to sensitively depend on the number of nodes $N$ in a curious
erratic manner, and experimentally demonstrate its robustness against
perturbations from the contact and parasitic impedance of individual
components. This novel impedance anomaly is traced back to a generalized
resonance condition reminiscent of the Harper's equation for electronic lattice
transport in a magnetic field, even though our circuit network does not involve
magnetic translation symmetry. It reveals an emergent fractal parametric
structure of anomalous impedance peaks for different $N$ which cannot be
reconciled from a continuum theory and which does not correspond to regular
waveguide resonant behavior. This anomalous fractal scaling extends to the
transport properties of generic systems described by a network Laplacian,
whenever a resonance frequency scale is simultaneously present.


title:
Near-infrared spectra of the inflated post-common envelope brown dwarf
  NLTT 5306B

abstract:
  NLTT 5306 is a post-common envelope binary made up of a white dwarf host and
brown dwarf companion that has shown evidence of inflation and active mass
donation despite not filling its Roche lobe. Two proposed mechanisms for the
brown dwarf's inflation are magnetic interactions and a high metallicity,
cloudy atmosphere. We present moderate resolution ($R\lesssim2000$) $J$ band
Keck/NIRSPEC observations of this system. These phase-resolved data allow us to
constrain differences between atmospheric parameters of the day- and night-side
of the brown dwarf. Our day- and night-side effective temperature measurements
are consistent, in agreement with the brightness temperatures measurements from
Casewell et al. 2021a. The day-side favors a slightly lower surface gravity,
perhaps stemming from the material streaming between the two objects. Finally,
our data show a preference for low metallicity models. This would be expected
from the system's old age, but provides direct evidence that a high
metallicity, cloudy brown dwarf atmosphere is not responsible for the witnessed
inflation. These results strengthen the case for magnetic interactions leading
to inflation of NLTT 5306 B.


title: The Tadpole Conjecture in Asymptotic Limits

abstract:
  The tadpole conjecture suggests that the complete stabilization of complex
structure deformations in Type IIB and F-theory flux compactifications is
severely obstructed by the tadpole bound on the fluxes. More precisely, it
states that the stabilization of a large number of moduli requires a flux
background with a tadpole that scales linearly in the number of stabilized
fields. Restricting to the asymptotic regions of the complex structure moduli
space, we give the first conceptual argument that explains this linear scaling
setting and clarifies why it sets in only for a large number of stabilized
moduli. Our approach relies on the use of asymptotic Hodge theory. In
particular, we use the fact that in each asymptotic regime an orthogonal
sl(2)-block structure emerges that allows us to group fluxes into
sl(2)-representations and decouple complex structure directions. We show that
the number of stabilized moduli scales with the number of sl(2)-representations
supported by fluxes, and that each representation fixes a single modulus.
Furthermore, we find that for Calabi-Yau four-folds all but one representation
can be identified with representations occurring on two-folds. This allows us
to discuss moduli stabilization explicitly and establish the relevant scaling
constraints for the tadpole.


title:
Evidence of Galaxy Assembly Bias in SDSS DR7 Galaxy Samples from Count
  Statistics

abstract:
  We present observational constraints on the galaxy-halo connection, focusing
particularly on galaxy assembly bias, from a novel combination of
counts-in-cylinders statistics, $P(N_{\rm{CIC}})$, with the standard
measurements of the projected two-point correlation function,
$w_{\rm{p}}(r_{\rm{p}})$, and number density, $n_{\rm{gal}}$, of galaxies. We
measure $n_{\rm{gal}}$, $w_{\rm{p}}(r_{\rm{p}})$ and $P(N_{\rm{CIC}})$ for
volume-limited, luminosity-threshold samples of galaxies selected from SDSS
DR7, and use them to constrain halo occupation distribution (HOD) models,
including a model in which galaxy occupation depends upon a secondary halo
property, namely halo concentration. We detect significant positive central
assembly bias for the $M_r<-20.0$ and $M_r<-19.5$ samples. Central galaxies
preferentially reside within haloes of high concentration at fixed mass.
Positive central assembly bias is also favoured in the $M_r<-20.5$ and
$M_r<-19.0$ samples. We find no evidence of central assembly bias in the
$M_r<-21.0$ sample. We observe only a marginal preference for negative
satellite assembly bias in the $M_r<-20.0$ and $M_r<-19.0$ samples, and
non-zero satellite assembly bias is not indicated in other samples. Our
findings underscore the necessity of accounting for galaxy assembly bias when
interpreting galaxy survey data, and demonstrate the potential of count
statistics in extracting information from the spatial distribution of galaxies,
which could be applied to both galaxy-halo connection studies and cosmological
analyses.


title: Dynamical descalarization with a jump during black hole merger

abstract:
  Black holes in scalar-Gauss-Bonnet gravity are prone to scalarization, that
is a spontaneous development of scalar hair for strong enough spacetime
curvature while the weak field regime of the theory coincides with general
relativity. Since large spacetime curvature is associated with smaller black
hole masses, the merging of black holes can lead to dynamical descalarization.
This is a spontaneous release of the scalar hair of the newly formed black hole
in case its mass is above the scalarization threshold. Depending on the exact
form of the Gauss-Bonnet coupling function, the stable scalarized solutions can
be either continuously connected to the Schwarzschild black hole, or the
transitions between the two can happen with a jump. By performing simulations
of black hole head-on collisions in scalar-Gauss-Bonnet gravity prone to
dynamical descalization, we have demonstrated that such a jump can be clearly
observed in the accumulated gravitational wave data of multiple merger events
with different masses. The distinct signature in the gravitational wave signal
will share similarities with the effects expected from first order matter phase
transitions happening during neutron star binary mergers.


title: Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT

abstract:
  We report 4 new pulsars discovered in the core-collapsed globular cluster
(GC) NGC 6624 by the TRAPUM Large Survey Project with the MeerKAT telescope.
All of the new pulsars found are isolated. PSR J1823$-$3021I and PSR
J1823$-$3021K are millisecond pulsars with period of respectively 4.319 ms and
2.768 ms. PSR J1823$-$3021J is mildly recycled with a period of 20.899 ms, and
PSR J1823$-$3022 is a long period pulsar with a period of 2.497 s. The pulsars
J1823$-$3021I, J1823$-$3021J, and J1823$-$3021K have position and dispersion
measure (DM) compatible with being members of the GC and are therefore
associated with NGC 6624. Pulsar J1823$-$3022 is the only pulsar bright enough
to be re-detected in archival observations of the cluster. This allowed the
determination of a timing solution that spans over two decades. It is not
possible at the moment to claim the association of pulsar J1823$-$3022 with the
GC given the long period and large offset in position ($\sim 3$ arcminutes) and
DM (with a fractional difference of 11 percent compared the average of the
pulsars in NGC 6624). The discoveries made use of the beamforming capability of
the TRAPUM backend to generate multiple beams in the same field of view which
allows sensitive searches to be performed over a few half-light radii from the
cluster center and can simultaneously localise the discoveries. The discoveries
reflect the properties expected for pulsars in core-collapsed GCs.


title:
Charged black holes in de Sitter space: superradiant amplification of
  charged scalar waves and resonant hyperradiation

abstract:
  Black holes typically inhabit highly dynamical galactic environments and are
frequently permeated by accretion media. The inevitable scattering of scalar,
electromagnetic and gravitational waves off rotating and charged black holes
provides a remarkable demonstration of the energy extraction and subsequent
amplification of scattered waves under the expense of the compact object's
rotational and electromagnetic energy; a phenomenon known as superradiance.
Certain circumstances tremendously favor the energy extraction process in such
extent that linear superradiant instabilities are triggered. We examine the
superradiant amplification of monochromatic charged scalar fields impinging
Reissner-Nordstr\"om-de Sitter black holes which are known to exhibit
superradiantly unstable quasinormal modes. We find that even though the
frequency range of superradiance is reduced when a positive cosmological
constant is incorporated, the amplification factors are significantly elevated
with respect to those occurring in Reissner-Nordstr\"om spacetime.
Intriguingly, we confirm that the long-lived quasinormal resonances that reside
in the superradiant regime induce resonant peaks when the wave's frequency
matches the real part of the quasinormal mode, regardless of the spacetime's
modal stability.


title:
Numerical relativity simulations of the neutron star merger GW190425:
  microphysics and mass ratio effects

abstract:
  GW190425 was the second gravitational wave (GW) signal compatible with a
binary neutron star (BNS) merger detected by the Advanced LIGO and Advanced
Virgo detectors. Despite intense follow-up campaigns, no electromagnetic
counterpart was identified. Whether the associated kilonova was too dim or the
localisation area too broad is still an open question. We simulate 28 BNS
mergers with the chirp mass of GW190425 and spanning a mass ratio $1 \leq q
\leq 1.67$, using numerical-relativity simulations with finite temperature,
composition dependent nuclear equation of state (EOS) and neutrino radiation.
The energy emitted in GWs is $\lesssim 0.083 M_{\odot} c^2$ with a peak
luminosity of $1.1-2.4 \times 10^{58} {\rm erg~s^{-1}}/(1+q)^2$. Dynamical
ejecta and disc mass are relatively small, the former ranging between $5 \times
10^{-6}$ and $\sim 10^{-3}~M_{\odot}$ and the latter between $10^{-5}$ and
$0.1~M_{\odot}$. Asymmetric mergers, especially in the case of stiff EOS, are
able to unbind more matter and to form heavier discs compared to equal mass
binaries. The angular momentum of the disc is $8-10 M_{\odot}~GM_{\rm disc}/c$
over three orders of magnitude in $M_{\rm disc}$. While the associated
nucleosynthesis shows no peculiarity, the simulated kilonovae are relatively
dim compared with the GW170817 event. In particular, for distances compatible
with GW190425, we find AB magnitudes always dimmer than $\sim20~{\rm mag}$ for
the $B$, $r$ and $K$ bands, with brighter kilonovae associated to more
asymmetric binaries and stiffer EOS. We suggest that, even assuming a good
coverage of GW190425's sky location, the kilonova signal could hardly have been
detected by present wide-field surveys and no firm constraints on the binary
parameters or neutron star (NS) EOS can be argued from the lack of the
detection.


title: The Sensitivity of Future Gamma-Ray Telescopes to Primordial Black Holes

abstract:
  The strongest existing constraints on primordial black holes with masses in
the range of $m_{\rm BH} \sim 10^{15}-10^{17} \, {\rm g}$ have been derived
from measurements of the local cosmic-ray electron-positron flux by Voyager 1,
and MeV-scale gamma-ray observations of the Inner Galaxy by COMPTEL and
INTEGRAL. In this paper, we evaluate the sensitivity of future MeV-scale
gamma-ray telescopes such as e-ASTROGAM or AMEGO to Hawking radiation. We show
that such an instrument would be able to provide the strongest constraints on
black holes in the mass range of $m_{\rm BH} \sim (0.6-20) \times 10^{16} \,
{\rm g}$, typically exceeding current constraints by approximately two orders
of magnitude. In scenarios in which the observed 511 keV excess is the result
of Hawking radiation, we find that e-ASTROGAM or AMEGO would not only be able
to detect the Hawking radiation from the Inner Galaxy, but could precisely
measure the abundance and mass distribution of the black holes responsible for
this signal.


title:
Cosmic Reionization on Computers: Physical Origin of Long Dark Gaps in
  Quasar Absorption Spectra

abstract:
  I explore the properties of "dark gaps" - regions in quasar absorption
spectra without significant transmission - with several simulations from the
Cosmic Reionization On Computers (CROC) project. CROC simulations in largest
available boxes (120 cMpc) come close to matching both the distribution of mean
opacities and the frequency of dark gaps, but alas not in the same model: the
run that matches the mean opacities fails to contain enough dark gaps and vice
versa.:( Never-the-less, the run that matches the dark gap distributions serves
as a counter-example to claims in the literature that the dark gap statistics
requires a late end to reionization - in that run reionization ends at z=6.7
(likely too early).
  While multiple factors contribute to the frequency of large dark gaps in the
simulations, the primary factor that controls the overall shape of the dark gap
distribution is the ionization level in voids - the lowest density regions
produce the highest transmission spikes that terminate long gaps. As the
result, the dark gap distribution correlates strongly with the fraction of the
spectrum above the gap detection threshold, the observed distribution is
matched by the simulation in which this fraction is 2%. Hence, the gap
distribution by itself does not constrain the timing of reionization.


title:
Accelerating the approach of dissipative quantum spin systems towards
  stationarity through global spin rotations

abstract:
  We consider open quantum systems whose dynamics is governed by a
time-independent Markovian Lindblad Master equation. Such systems approach
their stationary state on a timescale that is determined by the spectral gap of
the generator of the Master equation dynamics. In the recent paper [Carollo et
al., Phys. Rev. Lett. 127, 060401 (2021)] it was shown that under certain
circumstances it is possible to exponentially accelerate the approach to
stationarity by performing a unitary transformation of the initial state. This
phenomenon can be regarded as the quantum version of the so-called Mpemba
effect. The transformation of the initial state removes its overlap with the
dynamical mode of the open system dynamics that possesses the slowest decay
rate and thus determines the spectral gap. While this transformation can be
exactly constructed in some cases, it is in practice challenging to implement.
Here we show that even far simpler transformations constructed by a global
unitary spin rotation allow to exponentially speed up relaxation. We
demonstrate this using simple dissipative quantum spin systems, which are
relevant for current quantum simulation and computation platforms based on
trapped atoms and ions.


title: Symmetry protected exceptional points of interacting fermions

abstract:
  Non-hermitian quantum systems can exhibit spectral degeneracies known as
exceptional points, where two or more eigenvectors coalesce, leading to a
non-diagonalizable Jordan block. It is known that symmetries can enhance the
abundance of exceptional points in non-interacting systems. Here, we
investigate the fate of such symmetry protected exceptional points in the
presence of a symmetry preserving interaction between two fermions and find
that, (i) exceptional points are stable in the presence of the interaction.
Their propagation through the parameter space leads to the formation of
characteristic exceptional "fans". In addition, (ii) we identify a new source
for exceptional points which are only present due to the interaction. These
points emerge from diagonalizable degeneracies in the non-interacting case.
Beyond their creation and stability, (iii) we also find that exceptional points
can annihilate each other if they meet in parameter space with compatible
many-body states forming a third order exceptional point at the endpoint. These
phenomena are well captured by an "exceptional perturbation theory" starting
from a non-interacting Hamiltonian.


title:
Excitations in the Higher Lattice Gauge Theory Model for Topological
  Phases II: the 2+1d Case

abstract:
  In this work, the second paper of this series, we study the 2+1d version of a
Hamiltonian model for topological phases based on higher lattice gauge theory.
We construct the ribbon operators that produce the point-like excitations.
These ribbon operators are used to find the braiding properties and topological
charge carried by the point-like excitations. The model also hosts loop-like
excitations, which are produced by membrane operators. By considering a change
of basis, we show that, in certain cases, some loop-like excitations represent
domain walls between patches corresponding to different symmetry-related ground
states, and we find this symmetry. We also map the higher lattice gauge theory
Hamiltonian to the symmetry enriched string-net model for symmetry enriched
topological phases (SETs) described by Heinrich, Burnell, Fidkowski and Levin
[Phys. Rev. B, 94 (2016)], again in a subset of cases.


title: Phonon-induced modification of quantum criticality

abstract:
  We study the effect of acoustic phonons on the quantum phase transition in
the O($N$) model. We develop a renormalization group analysis near (3+1)
space-time dimensions and derive the RG equations using an
$\epsilon$-expansion. Our results indicate that when the number of flavors of
the underlying O($N$) model exceeds a critical number $N_c=4$, the quantum
transition remains second-order of the Wilson-Fisher type while, for $N\le 4$,
it is a weakly first-order transition. We characterize this weakly first-order
transition by a length-scale $\xi^*$, below which the behavior appears to be
critical. At finite temperatures for $N\le 4$, a tricritical point separates
the weakly first-order and second-order transitions.


title:
Extreme Mass Ratio Inspirals triggered by Massive Black Hole Binaries:
  from Relativistic Dynamics to Cosmological Rates

abstract:
  Extreme mass ratio inspirals (EMRIs) are compact binary systems characterized
by a mass-ratio $q=m/M$ in the range $~10^{-9}-10^{-4}$ and represent primary
gravitational wave (GW) sources for the forthcoming Laser Interferometer Space
Antenna (LISA). While their standard formation channel involves relaxation
processes deflecting compact objects on very low angular momentum orbits around
the central massive black hole, a number of alternative formation channels has
been proposed, including binary tidal break-up, migration in accretion disks
and secular and chaotic dynamics around a massive black hole binary (MBHB). In
this work, we take an extensive closer look at this latter scenario,
investigating how EMRIs can be triggered by a MBHBs, formed in the aftermath of
galaxy mergers. By employing a suite of relativistic three-body simulations, we
evaluate the efficiency of EMRI formation for different parameters of the MBHB,
assessing the importance of both secular and chaotic dynamics. By modelling the
distribution of compact objects in galaxy nuclei, we estimate the resulting
EMRI formation rate, finding that EMRI are produced in a sharp burst, with peak
rates that are 10-100 times higher than the standard two-body relaxation
channel, lasting for 10$^6$--10$^8$ years. By coupling our results with an
estimate of the cosmic MBHB merger rate, we finally forecast that LISA could
observe ${\cal O}(10)$ EMRIs per year formed by this channel.


title: Gas Accretion Can Drive Turbulence in Galaxies

abstract:
  The driving of turbulence in galaxies is deeply connected with the physics of
feedback, star formation, outflows, accretion, and radial transport in disks.
The velocity dispersion of gas in galaxies therefore offers a promising
observational window into these processes. However, the relative importance of
each of these mechanisms remains controversial. In this work we revisit the
possibility that turbulence on galactic scales is driven by the direct impact
of accreting gaseous material on the disk. We measure this effect in a
disk-like star-forming galaxy in IllustrisTNG, using the high-resolution
cosmological magnetohydrodynamical simulation TNG50. We employ Lagrangian
tracer particles with a high time cadence of only a few Myr to identify
accretion and other events, such as star formation, outflows, and movement
within the disk. The energies of particles as they arrive in the disk are
measured by stacking the events in bins of time before and after the event. The
average effect of each event is measured on the galaxy by fitting explicit
models for the kinetic and turbulent energies as a function of time in the
disk. These measurements are corroborated by measuring the cross-correlation of
the turbulent energy in the different annuli of the disk with other time
series, and searching for signals of causality, i.e. asymmetries in the
cross-correlation across zero time lag. We find that accretion contributes to
the large-scale turbulent kinetic energy even if it is not the dominant driver
of turbulence in this $\sim 5 \times 10^{9} M_\odot$ stellar mass galaxy.
Extrapolating this finding to a range of galaxy masses, we find that there are
regimes where energy from direct accretion may dominate the turbulent energy
budget, particularly in disk outskirts, galaxies less massive than the Milky
Way, and at redshift $\sim 2$.


title:
Towards Automatically Generating Release Notes using Extractive
  Summarization Technique

abstract:
  Release notes are admitted as an essential document by practitioners. They
contain the summary of the source code changes for the software releases, such
as issue fixes, added new features, and performance improvements. Manually
producing release notes is a time-consuming and challenging task. For that
reason, sometimes developers neglect to write release notes. For example, we
collect data from GitHub with over 1,900 releases, among them 37% of the
release notes are empty. We propose an automatic generate release notes
approach based on the commit messages and merge pull-request (PR) titles to
mitigate this problem. We implement one of the popular extractive text
summarization techniques, i.e., the TextRank algorithm. However, accurate
keyword extraction is a vital issue in text processing. The keyword matching
and topic extraction process of the TextRank algorithm ignores the semantic
similarity among texts. To improve the keyword extraction method, we integrate
the GloVe word embedding technique with TextRank. We develop a dataset with
1,213 release notes (after null filtering) and evaluate the generated release
notes through the ROUGE metric and human evaluation. We also compare the
performance of our technique with another popular extractive algorithm, latent
semantic analysis (LSA). Our evaluation results show that the improved TextRank
method outperforms LSA.


title:
Criticality and phase classification for quadratic open quantum
  many-body systems

abstract:
  We study the steady states of translation-invariant open quantum many-body
systems governed by Lindblad master equations, where the Hamiltonian is
quadratic in the ladder operators, and the Lindblad operators are either linear
or quadratic and Hermitian. These systems are called quasi-free and quadratic,
respectively. We find that steady states of one-dimensional systems with
finite-range interactions necessarily have exponentially decaying Green's
functions. For the quasi-free case without quadratic Lindblad operators, we
show that fermionic systems with finite-range interactions are non-critical for
any number of spatial dimensions and provide bounds on the correlation lengths.
Quasi-free bosonic systems can be critical in $D>1$ dimensions. Lastly, we
address the question of phase transitions in quadratic systems and find that,
without symmetry constraints beyond invariance under single-particle basis and
particle-hole transformations, all gapped Liouvillians belong to the same
phase.


title:
Regularity Results for Solutions of Autonomous Obstacle Problems with
  General Growth

abstract:
  Considering the problem \begin{equation*} \min_{v} \int_\Omega F(Dv(x)) \,
dx, \end{equation*} on a specific class of admissible functions, where we
suppose the Lagrangian satisfies proper hypotheses of convexity and super
linearity at infinity, our aim is to characterize the solutions by mean of a
primal-dual formulation of the problem. Our research is based on classical
arguments of Convex Analysis.


title:
The Minimal Supersymmetric Standard Model (MSSM) with $R$-Parity
  Violation

abstract:
  In this lectures, we give a review about the Minimal Supersymmetric Standard
Model (MSSM) with $R$-Parity Violation because it provides an attractive way to
generate neutrino masses, lepton mixing angles in acconcordance to present
neutrino data.


title:
Compression of a confined semiflexible polymer under direct and
  oscillating fields

abstract:
  The folding transition of biopolymers from the coil to compact structures has
attracted wide research interest in the past and is well studied in polymer
physics. Recent seminal works on DNA in confined devices have shown that these
long biopolymers tend to collapse under an external field, contrary to the
previously reported stretching. These long folded structures have a tendency to
form knots that has profound implications in gene regulation and various other
biological functions. These knots have been mechanically induced via optical
tweezers, nanochannel confinement, etc., until recently, where uniform field
driven compression lead to self entanglement of DNA. In this work, we capture
the compression of a confined semiflexible polymer under direct and oscillating
fields, using a coarse-grained computer simulation model in the presence of
long-range hydrodynamics. Within this framework, we show that subjected to
direct field, chains in stronger confinements exhibit substantial compaction,
contrary to the one in moderate confinements or bulk, where such compaction is
absent. Interestingly, an alternating field within an optimum frequency can
effectuate this compression even in moderate or no confinement. Additionally,
we show that the bending rigidity has a profound influence on the chains
folding favourability under direct and alternating fields. This field induced
collapse is a quintessential hydrodynamic phenomenon, resulting in intertwined
knotted structures, even for shorter chains, unlike DNA knotting experiments,
where it happens exclusively for longer chains.


title: Leveraging Deep Neural Networks for Massive MIMO Data Detection

abstract:
  Massive multiple-input multiple-output (MIMO) is a key technology for
emerging next-generation wireless systems. Utilizing large antenna arrays at
base-stations, massive MIMO enables substantial spatial multiplexing gains by
simultaneously serving a large number of users. However, the complexity in
massive MIMO signal processing (e.g., data detection) increases rapidly with
the number of users, making conventional hand-engineered algorithms less
computationally efficient. Low-complexity massive MIMO detection algorithms,
especially those inspired or aided by deep learning, have emerged as a
promising solution. While there exist many MIMO detection algorithms, the aim
of this magazine paper is to provide insight into how to leverage deep neural
networks (DNN) for massive MIMO detection. We review recent developments in
DNN-based MIMO detection that incorporate the domain knowledge of established
MIMO detection algorithms with the learning capability of DNNs. We then present
a comparison of the key numerical performance metrics of these works. We
conclude by describing future research areas and applications of DNNs in
massive MIMO receivers.


title: Graph Ordering Attention Networks

abstract:
  Graph Neural Networks (GNNs) have been successfully used in many problems
involving graph-structured data, achieving state-of-the-art performance. GNNs
typically employ a message-passing scheme, in which every node aggregates
information from its neighbors using a permutation-invariant aggregation
function. Standard well-examined choices such as the mean or sum aggregation
functions have limited capabilities, as they are not able to capture
interactions among neighbors. In this work, we formalize these interactions
using an information-theoretic framework that notably includes synergistic
information. Driven by this definition, we introduce the Graph Ordering
Attention (GOAT) layer, a novel GNN component that captures interactions
between nodes in a neighborhood. This is achieved by learning local node
orderings via an attention mechanism and processing the ordered representations
using a recurrent neural network aggregator. This design allows us to make use
of a permutation-sensitive aggregator while maintaining the
permutation-equivariance of the proposed GOAT layer. The GOAT model
demonstrates its increased performance in modeling graph metrics that capture
complex information, such as the betweenness centrality and the effective size
of a node. In practical use-cases, its superior modeling capability is
confirmed through its success in several real-world node classification
benchmarks.


title:
Large-Scale Streaming End-to-End Speech Translation with Neural
  Transducers

abstract:
  Neural transducers have been widely used in automatic speech recognition
(ASR). In this paper, we introduce it to streaming end-to-end speech
translation (ST), which aims to convert audio signals to texts in other
languages directly. Compared with cascaded ST that performs ASR followed by
text-based machine translation (MT), the proposed Transformer transducer
(TT)-based ST model drastically reduces inference latency, exploits speech
information, and avoids error propagation from ASR to MT. To improve the
modeling capacity, we propose attention pooling for the joint network in TT. In
addition, we extend TT-based ST to multilingual ST, which generates texts of
multiple languages at the same time. Experimental results on a large-scale 50
thousand (K) hours pseudo-labeled training set show that TT-based ST not only
significantly reduces inference time but also outperforms non-streaming
cascaded ST for English-German translation.


title: Off-axis runaway-electron seed formation, growth and suppression

abstract:
  Novel x-ray detection technology enabled the first profile measurements of
the birth and growth dynamics of runaway electrons (REs) at the edge of
tokamaks during quiescent RE studies at the Madison Symmetric Torus. The
formation of an off-axis RE seed with linear growth rates has been resolved for
low energies, a hollow streaming parameter and large electric fields
($E_{\parallel}/E_{D}$) in agreement with theory and simulations. Secondary
exponential growth rates have also been spatially resolved for the first time
and are consistent with a convective transport of the order of the Ware pinch
and energies up to $10^3\times T_{e,0}$. Numerical simulations are shown to
reproduce the experimental observations including the off-axis runaway electron
generation, radial transport and exponential growth at the core, as well as
suppression due to $m=3$ resonant magnetic perturbations.


title:
Study of pion production in $\nu_{\mu}$ interactions on $^{40}$Ar in
  DUNE using GENIE and NuWro event generators

abstract:
  The study of pion production and the effects of final state interactions
(FSI) are important for data analysis in all neutrino experiments. For energies
at which current neutrino experiments are being operated, a significant
contribution to pion production is made by resonance production process. After
its production, if a pion is absorbed in the nuclear matter, the event may
become indistinguishable from quasi-elastic scattering process and acts as a
background. The estimation of this background is very essential for oscillation
experiments and requires good theoretical models for both pion production at
primary vertex and after FSI. Due to FSI, the number of final state pions is
significantly different from the number produced at primary vertex. As the
neutrino detectors can observe only the final state particles, the correct
information about the particles produced at the primary vertex is overshadowed
by FSI. To overcome this difficulty, a good knowledge of FSI is required which
may be provided by theoretical models incorporated in Monte Carlo (MC) neutrino
event generators. In this work, we will present simulated events for two
different MC generators - GENIE and NuWro, for pion production in $\nu_{\mu}$CC
interactions on $^{40}$Ar target in DUNE experimental set up. A brief outline
of theoretical models used by generators is presented. The results of pion
production are presented in the form of tables showing the occupancy of primary
and final state pion topologies with 100$\%$ detector resolution and with
kinetic energy detector threshold cuts. We observe that NuWro (v-19.02.2) is
more transparent (less responsive) to absorption and charge exchange processes
as compared to GENIE (v-3.00.06), pions are more likely to be absorbed than
created during their intranuclear transport and there is need to improve
detector technology to improve the detector threshold for better results.


title:
Exploring Relevant Artifacts of Release Notes: The Practitioners'
  Perspective

abstract:
  A software release note is one of the essential documents in the software
development life cycle. The software release contains a set of information,
e.g., bug fixes and security fixes. Release notes are used in different phases,
e.g., requirement engineering, software testing and release management.
Different types of practitioners (e.g., project managers and clients) get
benefited from the release notes to understand the overview of the latest
release. As a result, several studies have been done about release notes
production and usage in practice. However, two significant problems (e.g.,
duplication and inconsistency in release notes contents) exist in producing
well-written & well-structured release notes and organizing appropriate
information regarding different targeted users' needs. For that reason,
practitioners face difficulties in writing and reading the release notes using
existing tools. To mitigate these problems, we execute two different studies in
our paper. First, we execute an exploratory study by analyzing 3,347 release
notes of 21 GitHub repositories to understand the documented contents of the
release notes. As a result, we find relevant key artifacts, e.g., issues (29%),
pull-requests (32%), commits (19%), and common vulnerabilities and exposures
(CVE) issues (6%) in the release note contents. Second, we conduct a survey
study with 32 professionals to understand the key information that is included
in release notes regarding users' roles. For example, project managers are more
interested in learning about new features than less critical bug fixes. Our
study can guide future research directions to help practitioners produce the
release notes with relevant content and improve the documentation quality.


title: A Generative Language Model for Few-shot Aspect-Based Sentiment Analysis

abstract:
  Sentiment analysis is an important task in natural language processing. In
recent works, pre-trained language models are often used to achieve
state-of-the-art results, especially when training data is scarce. It is common
to fine-tune on the downstream task, usually by adding task-specific layers on
top of the model. In this paper, we focus on aspect-based sentiment analysis,
which involves extracting aspect term, category, and predicting their
corresponding polarities. In particular, we are interested in few-shot
settings. We propose to reformulate the extraction and prediction tasks into
the sequence generation task, using a generative language model with
unidirectional attention (GPT2 is used unless stated otherwise). This way, the
model learns to accomplish the tasks via language generation without the need
of training task-specific layers. Our evaluation results on the single-task
polarity prediction show that our approach outperforms the previous
state-of-the-art (based on BERT) on average performance by a large margins in
few-shot and full-shot settings. More importantly, our generative approach
significantly reduces the model variance caused by low-resource data. We
further demonstrate that the proposed generative language model can handle
joint and multi-task settings, unlike previous work. We observe that the
proposed sequence generation method achieves further improved performances on
polarity prediction when the model is trained via joint and multi-task
settings. Further evaluation on similar sentiment analysis datasets, SST-2,
SST- and OOS intent detection validates the superiority and noise robustness of
generative language model in few-shot settings.


title:
Bias induced drift and trapping on random combs and the Bethe lattice:
  Fluctuation regime and first order phase transitions

abstract:
  We study the competition between field-induced transport and trapping in a
disordered medium by studying biased random walks on random combs and the
bond-diluted Bethe lattice above the percolation threshold. While it is known
that the drift velocity vanishes above a critical threshold, here our focus is
on fluctuations, characterized by the variance of the transit times. On the
random comb, the variance is calculated exactly for a given realization of
disorder using a 'forward transport' limit which prohibits backward movement
along the backbone but allows an arbitrary number of excursions into
random-length branches. The disorder-averaged variance diverges at an earlier
threshold of the bias, implying a regime of anomalous fluctuations, although
the velocity is nonzero. Our results are verified numerically using a Monte
Carlo procedure that is adapted to account for ultra-slow returns from long
branches. On the Bethe lattice, we derive an upper bound for the critical
threshold bias for anomalous fluctuations of the mean transit time averaged
over disorder realizations. Finally, as for the passage to the vanishing
velocity regime, it is shown that the transition to the anomalous fluctuation
regime can change from continuous to first order depending on the distribution
of branch lengths.


title: A Concurrent Switching Model for Traffic Congestion Control

abstract:
  We introduce a new conservation-based approach for traffic coordination
modeling and control in a network of interconnected roads (NOIR) with switching
movement phase rotations at every NOIR junction. For modeling of traffic
evolution, we first assume that the movement phase rotation is cyclic at every
NOIR junction, but the duration of each movement phase can be arbitrarily
commanded by traffic signals. Then, we propose a novel concurrent switching
dynamics (CSD) with deterministic transitions among a finite number of states,
representing the NOIR movement phases. We define the CSD control as a cyclic
receding horizon optimization problem with periodic quadratic cost and
constraints. More specifically, the cost is defined so that the traffic density
is minimized and the boundary inflow is uniformly distributed over the boundary
inlet roads, whereas the cost parameters are periodically changed with time.
The constraints are linear and imposed by a trapezoidal fundamental diagram at
every NOIR road so that traffic feasibility is assured and traffic
over-saturation is avoided. The success of the proposed traffic boundary
control is demonstrated by simulation of traffic congestion control in Downtown
Phoenix.


title:
$\nu$-Analysis: A New Notion of Robustness for Large Systems with
  Structured Uncertainties

abstract:
  We present a new, scalable alternative to the structured singular value,
which we call $\nu$, provide a convex upper bound, study their properties and
compare them to $\ell_1$ robust control. The analysis relies on a novel result
on the relationship between robust control of dynamical systems and
non-negative constant matrices.


title:
Disruption of a Planetary Nitrogen Cycle as Evidence of Extraterrestrial
  Agriculture

abstract:
  Agriculture is one of the oldest forms of technology on Earth. The
cultivation of plants requires a terrestrial planet with active hydrological
and carbon cycles and depends on the availability of nitrogen in soil. The
technological innovation of agriculture is the active management of this
nitrogen cycle by applying fertilizer to soil, at first through the production
of manure excesses but later by the Haber-Bosch industrial process. The use of
such fertilizers has increased the atmospheric abundance of nitrogen-containing
species such as NH$_3$ and N$_2$O as agricultural productivity intensifies in
many parts of the world. Both NH$_3$ and N$_2$O are effective greenhouse gases,
and the combined presence of these gases in the atmosphere of a habitable
planet could serve as a remotely detectable spectral signature of technology.
Here we use a synthetic spectral generator to assess the detectability of
NH$_3$ and N$_2$O that would arise from present-day and future global-scale
agriculture. We show that present-day Earth abundances of NH$_3$ and N$_2$O
would be difficult to detect but hypothetical scenarios involving a planet with
30-100 billion people could show a change in transmittance of about 50-70%
compared to pre-agricultural Earth. These calculations suggest the possibility
of considering the simultaneous detection of NH$_3$ and N$_2$O in an atmosphere
that also contains H$_2$O, O$_2$, and CO$_2$ as a technosignature for
extraterrestrial agriculture. The technology of agriculture is one that could
be sustainable across geologic timescales, so the spectral signature of such an
"ExoFarm" is worth considering in the search for technosignatures.


title:
Non-thermal emission from fall-back clouds in the Broad-Line Region of
  Active Galactic Nuclei

abstract:
  The spectra of active galactic nuclei exhibit broad-emission lines that
presumably originate in the Broad-Line Region (BLR) with gaseous-dusty clouds
in a predominantly Keplerian motion around the central black hole. Signatures
of both inflow and outflow motion are frequently seen. The dynamical character
of BLR is consistent with the scenario that has been branded as the Failed
Radiatively Accelerated Dusty Outflow (FRADO; Czerny & Hryniewicz 2011). In
this scheme, frequent high-velocity impacts of BLR clouds falling back onto the
underlying accretion disk are predicted. The impact velocities depend mainly on
the black-hole mass, accretion rate, and metallicity and they range from a few
km s$^{-1}$ up to thousands of km s$^{-1}$. Formation of strong shocks due to
the collisions can give rise to the production of relativistic particles and
associated radiation signatures. In this work, the non-thermal radiation
generated in this process is investigated, and the spectral energy
distributions for different parameter sets are presented. We find that the
non-thermal processes caused by the impacts of clouds can lead to emission in
the X-ray and the gamma-ray bands, playing the cloud density and metallicity a
key role.


title:
Assuming Ionization Equilibrium and the Impact on the
  Lyman-$\mathrm{\alpha}$ Forest Power Spectrum during the End of Reionization
  at $8 \geq z \geq 5$

abstract:
  We explore how the assumption of ionization equilibrium modulates the modeled
intergalactic medium (IGM) at the end of the hydrogen Epoch of Reionization
using the cosmological radiation hydrodynamic \textsc{Technicolor Dawn}
simulation. In neutral and partially-ionized regions where the metagalactic
ultraviolet background (UVB) is weak, the ionization timescale
$t_\mathrm{ion}\equiv \Gamma^{-1}$ exceeds the Hubble time. Assuming
photoionization equilibrium in such regions artificially boosts the ionization
rate, accelerating reionization. By contrast, the recombination time
$t_\mathrm{rec} < t_\mathrm{ion}$ in photoionized regions, with the result that
assuming photoionization equilibrium artificially increases the neutral
hydrogen fraction. Using snapshots between $8 \geq z \geq 5$, we compare the
predicted Lyman-$\alpha$ forest flux power spectrum with and without the
assumption of ionization equilibrium. Small scales ($k > 0.1$ rad s km$^{-1}$)
exhibit reduced power from $7 \leq z \leq 5.5$ in the ionization equilibrium
case while larger scales are unaffected. This occurs for the same reasons:
ionization equilibrium artificially suppresses the neutral fraction in
self-shielded gas and boosts ionizations in voids, suppressing small-scale
fluctuations in the ionization field. When the volume-averaged neutral fraction
drops below $10^{-4}$, the signature of non-equilibrium ionizations on the
Lyman-$\alpha$ forest (LAF) disappears. Comparing with recent observations
indicates that these non-equilibrium effects are not yet observable in the LAF
flux power spectrum.


title:
Trace Expansions and Equivariant Traces on an Algebra of Fourier
  Integral Operators on $\mathbb R^n$

abstract:
  We consider the operator algebra $\mathscr A$ on $\mathscr S(\mathbb R^n)$
generated by the Shubin type pseudodifferential operators, the Heisenberg-Weyl
operators and the lifts of the unitary operators on $\mathbb C^n$ to
metaplectic operators.
  With the help of an auxiliary operator in the Shubin calculus, we find trace
expansions for these operators in the spirit of Grubb and Seeley. Moreover, we
can define a noncommutative residue generalizing that for the Shubin
pseudodifferential operators and obtain a class of localized equivariant traces
on the algebra.


title:
Aharonov-Bohm oscillations in phosphorene quantum rings: mass anisotropy
  compensation by confinement potential

abstract:
  We consider the Aharonov-Bohm (AB) effect on a confined electron ground state
in a quantum ring defined electrostatically within the phosphorene monolayer.
The strong anisotropy of effective masses in phosphorene quenches ground-state
oscillations for a circular ring because of interrupted persistent current
circulation around the ring. An elliptic deformation of the confinement
potential can compensate for the anisotropy of the effective masses and produce
ground-state parity transformations with the AB periodicity. Moreover, a
specific ratio of the semiaxes is determined for which the spectrum becomes
identical to that of a circular quantum ring and an isotropic effective mass.
We identify a generalized angular momentum operator which commutes with the
continuum Hamiltonian for the chosen ratio of the semi-axes that closes the
avoided crossings of energy levels for states of the same parity and spin.
Ground-state oscillations for the two-electron ground state are also discussed.


title:
PolyARBerNN: A Neural Network Guided Solver and Optimizer for Bounded
  Polynomial Inequalities

abstract:
  Constraints solvers play a significant role in the analysis, synthesis, and
formal verification of complex embedded and cyber-physical systems. In this
paper, we study the problem of designing a scalable constraints solver for an
important class of constraints named polynomial constraint inequalities (also
known as non-linear real arithmetic theory). In this paper, we introduce a
solver named PolyARBerNN that uses convex polynomials as abstractions for
highly nonlinear polynomials. Such abstractions were previously shown to be
powerful to prune the search space and restrict the usage of sound and complete
solvers to small search spaces. Compared with the previous efforts on using
convex abstractions, PolyARBerNN provides three main contributions namely (i) a
neural network guided abstraction refinement procedure that helps selecting the
right abstraction out of a set of pre-defined abstractions, (ii) a Bernstein
polynomial-based search space pruning mechanism that can be used to compute
tight estimates of the polynomial maximum and minimum values which can be used
as an additional abstraction of the polynomials, and (iii) an optimizer that
transforms polynomial objective functions into polynomial constraints (on the
gradient of the objective function) whose solutions are guaranteed to be close
to the global optima. These enhancements together allowed the PolyARBerNN
solver to solve complex instances and scales more favorably compared to the
state-of-art non-linear real arithmetic solvers while maintaining the soundness
and completeness of the resulting solver. In particular, our test benches show
that PolyARBerNN achieved 100X speedup compared with Z3 8.9, Yices 2.6, and
NASALib (a solver that uses Bernstein expansion to solve multivariate
polynomial constraints) on a variety of standard test benches.


title:
Development of a 120-mm Aperture Nb3Sn Dipole Coil with Stress
  Management

abstract:
  This paper describes a 120-mm aperture 2-layer dipole coil with stress
management (SM) developed at Fermilab based on cos-theta coil geometry. A model
of the coil support structure made of plastic was printed using additive
manufacturing technology and used for practice coil winding. The real coil
support structure was printed using the 316 stainless steel. The results of the
SM structure size control and the key coil fabrication steps are reported in
the paper. The design of coil SM structure and the coil FEA in the dipole
mirror test configurations are presented and discussed.


title:
Branch Points for (Almost-)Minimizers of Two-Phase Free Boundary
  Problems

abstract:
  We study the existence and structure of branch points in two-phase free
boundary problems. More precisely, we construct a family of minimizers to an
Alt- Caffarelli-Friedman type functional whose free boundaries contain branch
points in the strict interior of the domain. We also give an example showing
that branch points in the free boundary of almost-minimizers of the same
functional can have very little structure. This last example stands in contrast
with recent results of De Philippis- Spolaor-Velichkov on the structure of
branch points in the free boundary of stationary solutions.


title: Massive Neutrinos, Dark Sector, and Hydrodynamics: The Sejong Suite

abstract:
  Improving the understanding of the processes governing small-scale nonlinear
clustering is a necessary task for interpreting upcoming high-quality
cosmological data, as it will allow one to break degeneracies and obtain tight
neutrino mass and warm dark matter constraints from large-scale structure
probes. The Sejong Suite, an extensive collection of state-of-the-art
high-resolution cosmological hydrodynamical simulations, has been intended with
this primary goal in mind. Spanning a large number of cosmological and
astrophysical parameters (especially suitable for the dark sector), and
organized into three main categories (Grid Suite, Supporting Suite, and
Systematics Suite), the release may be useful for a broader variety of
cosmological and astrophysical purposes - while primarily developed for
Lyman-Alpha (LyA) forest studies. In particular, the overall architecture of
the Grid Suite has been designed to achieve an equivalent resolution up to
3x3328^3=110 billion particles in a 100 Mpc/h box, corresponding to a 30 kpc/h
mean grid resolution, which ensures convergence on LyA flux statistics closer
to the desired 1.0% level that data from surveys such as the Dark Energy
Spectroscopic Instrument (DESI) will provide. Here, we briefly highlight the
main characteristics, improvements, and novelties of the Sejong Suite, as well
as ongoing and future applications.


title: Learning Implicit Priors for Motion Optimization

abstract:
  In this paper, we focus on the problem of integrating Energy-based Models
(EBM) as guiding priors for motion optimization. EBMs are a set of neural
networks that can represent expressive probability density distributions in
terms of a Gibbs distribution parameterized by a suitable energy function. Due
to their implicit nature, they can easily be integrated as optimization factors
or as initial sampling distributions in the motion optimization problem, making
them good candidates to integrate data-driven priors in the motion optimization
problem. In this work, we present a set of required modeling and algorithmic
choices to adapt EBMs into motion optimization. We investigate the benefit of
including additional regularizers in the learning of the EBMs to use them with
gradient-based optimizers and we present a set of EBM architectures to learn
generalizable distributions for manipulation tasks. We present multiple cases
in which the EBM could be integrated for motion optimization and evaluate the
performance of learned EBMs as guiding priors for both simulated and real robot
experiments.


title:
Panoptic, Instance and Semantic Relations: A Relational Context Encoder
  to Enhance Panoptic Segmentation

abstract:
  This paper presents a novel framework to integrate both semantic and instance
contexts for panoptic segmentation. In existing works, it is common to use a
shared backbone to extract features for both things (countable classes such as
vehicles) and stuff (uncountable classes such as roads). This, however, fails
to capture the rich relations among them, which can be utilized to enhance
visual understanding and segmentation performance. To address this shortcoming,
we propose a novel Panoptic, Instance, and Semantic Relations (PISR) module to
exploit such contexts. First, we generate panoptic encodings to summarize key
features of the semantic classes and predicted instances. A Panoptic Relational
Attention (PRA) module is then applied to the encodings and the global feature
map from the backbone. It produces a feature map that captures 1) the relations
across semantic classes and instances and 2) the relations between these
panoptic categories and spatial features. PISR also automatically learns to
focus on the more important instances, making it robust to the number of
instances used in the relational attention module. Moreover, PISR is a general
module that can be applied to any existing panoptic segmentation architecture.
Through extensive evaluations on panoptic segmentation benchmarks like
Cityscapes, COCO, and ADE20K, we show that PISR attains considerable
improvements over existing approaches.


title: Parametric Model Embedding

abstract:
  Methodologies for reducing the design-space dimensionality in shape
optimization have been recently developed based on unsupervised machine
learning methods. These methods provide reduced dimensionality representations
of the design space, capable of maintaining a certain degree of the original
design variability. Nevertheless, they usually do not allow to use the original
parameterization, representing a limitation to their widespread use in the
industrial field, where the design parameters often pertain to well-established
parametric models, e.g. CAD (computer aided design) models. This work presents
how to embed the parametric-model original parameters in a
reduced-dimensionality representation. The method, which takes advantage from
the definition of a newly-introduced generalized feature space, is demonstrated
to the reparameterization of a free-form deformation design space and the
consequent solution of a simulation-driven design optimization problem of a
naval destroyer in calm water.


title: ALMA constraints on assembly of Core Accretion planets

abstract:
  Resolved dust continuum and CO line ALMA imaging, and in some cases detection
of H$\alpha$ emission, hint that young massive planets are abundant at wide
separations in protoplanetary discs. Here, we show how these observations can
probe the runaway phase of planetary growth in the Core Accretion theory.
Planets in this phase have the right range of masses to account for the
predominantly moderate contrast gaps and rings seen in ALMA observations.
However, we find that these planets gain mass and migrate inward very rapidly.
As a result, the phase when they could produce gaps with properties similar to
those observed is very short, i.e., $t_{\rm gap} \lesssim 0.1$~Myr,
independently of the disc viscosity parameter. This would require many tens to
hundreds of gas giant planets to be born per ALMA system, violating the
available mass budget of solids in realistic discs. This also predicts
preponderance of discs with very wide gaps or complete inner disc holes, which
is not observed. We show that suppression of both planet accretion and
migration by a factor of at least ten is a possible solution to these serious
problems. Future population synthesis models of planet formation should aim to
address both exoplanetary data of older discless planetary systems and ALMA
discs with embedded planets in one framework.


title: Analysis of the Finite-State Ergodic Master Equation

abstract:
  Mean field games model equilibria in games with a continuum of players as
limiting systems of symmetric $n$-player games with weak interaction between
the players. We consider a finite-state, infinite-horizon problem with two cost
criteria: discounted and ergodic. Under the Lasry--Lions monotonicity condition
we characterize the stationary ergodic mean field game equilibrium by a mean
field game system of two coupled equations: one for the value and the other for
the stationary measure. This system is linked with the ergodic master equation.
Several discounted mean field game systems are utilized in order to set up the
relevant discounted master equations. We show that the discounted master
equations are smooth, uniformly in the discount factor. Taking the discount
factor to zero, we achieve the smoothness of the ergodic master equation.


title: Time periodic motion of temperature driven compressible fluids

abstract:
  We consider the Navier-Stokes-Fourier system describing the motion of a
compressible viscous fluid in a container with impermeable boundary subject to
time periodic heating and under the action of a time periodic potential force.
We show the existence of a time periodic weak solution for arbitrarily large
physically admissible data.


title: Experimental demonstration of OSC at IOTA: IOTA Run #3 Report

abstract:
  Optical Stochastic Cooling (OSC) is an optical-bandwidth extension of
Stochastic Cooling that could advance the state-of-the-art cooling rate in beam
cooling by three to four orders of magnitude [1-3]. The concept of OSC was
first suggested in the early 1990s by Zolotorev, Zholents and Mikhailichenko,
and replaced the microwave hardware of SC with optical analogs, such as
wigglers and optical amplifiers. A number of variations on the original OSC
concept have been proposed, and while a variety of proof-of-principle
demonstrations and operational uses have been considered, the concept was not
experimentally demonstrated up to now [4-9]. An OSC R&D program has been
underway at IOTA for the past several years [4]. Run #3 of the IOTA ring, which
began in Nov. 2020 and concluded in Aug. 2021, was focused on the worlds first
experimental demonstration of OSC. The experimental program was successful in
demonstrating and characterizing the OSC physics with the major outcomes
including strong cooling in one, two and three dimensions, validation of the
theoretical models of OSC and the demonstration of OSC with a single electron.
This report briefly describes the activities and major milestones of the OSC
program during Run #3. Detailed descriptions of the OSC theory, conceptual
design and hardware elements can be found in reference [4].


title:
medXGAN: Visual Explanations for Medical Classifiers through a
  Generative Latent Space

abstract:
  Despite the surge of deep learning in the past decade, some users are
skeptical to deploy these models in practice due to their black-box nature.
Specifically, in the medical space where there are severe potential
repercussions, we need to develop methods to gain confidence in the models'
decisions. To this end, we propose a novel medical imaging generative
adversarial framework, medXGAN (medical eXplanation GAN), to visually explain
what a medical classifier focuses on in its binary predictions. By encoding
domain knowledge of medical images, we are able to disentangle anatomical
structure and pathology, leading to fine-grained visualization through latent
interpolation. Furthermore, we optimize the latent space such that
interpolation explains how the features contribute to the classifier's output.
Our method outperforms baselines such as Gradient-Weighted Class Activation
Mapping (Grad-CAM) and Integrated Gradients in localization and explanatory
ability. Additionally, a combination of the medXGAN with Integrated Gradients
can yield explanations more robust to noise. The code is available at:
https://avdravid.github.io/medXGAN_page/.


title:
Magnetic order and spin liquid behavior in [Mo3+]^{11+} triangular
  magnets

abstract:
  Molecular magnets based on [Mo$_3$]$^{11+}$ units with one unpaired electron
per trimer have attracted recent interest due to the identification of quantum
spin liquid candidacy in some family members. Here, we present comprehensive
measurements on polycrystalline samples of ZnScMo$_3$O$_8$, MgScMo$_3$O$_8$,
and Na$_3$Sc$_2$Mo$_5$O$_{16}$ with the same Mo$_3$O$_{13}$ magnetic building
blocks. The crystal structures are characterized with x-ray or neutron powder
diffraction and the magnetic ground states are determined by performing ac and
dc susceptibility, specific heat, neutron powder diffraction, and $\mu$SR
measurements. Our work indicates that ZnScMo$_3$O$_8$ and MgScMo$_3$O$_8$ have
ferromagnetic Curie-Weiss temperatures of 18.5 K and 11.9 K, ordered ground
states with net moments (low-moment ferromagnetism or canted
antiferromagnetism), and zero field ordering temperatures of $T_c =$ 6 K and
$<$ 2 K respectively. On the other hand, Na$_3$Sc$_2$Mo$_5$O$_{16}$ hosts a
dynamical magnetic ground state with no evidence for magnetic ordering or spin
freezing down to 20 mK despite an antiferromagnetic Curie-Weiss temperature of
-36.2 K, and therefore is a candidate for quantum spin liquid behavior. By
comparing the present results to past work on the same family of materials, we
construct a phase diagram which illustrates that the magnetic ground states of
these Mo-based molecular magnets are very sensitive to small changes in the
nearest neighbor Mo-Mo distance.


title: Minimum Quench Energy Of Nb$_3$Sn Wires With High Specific Heat Tape

abstract:
  A major problem of state-of-the-art Nb$_3$Sn accelerator magnets is their
long training due to thermo-mechanical perturbations. Increasing the specific
heat, $C_p$, of the Rutherford cable would reduce and/or eliminate training by
limiting the coils temperature rise. This paper studies feasibility of
increasing the $C_p$ of Rutherford-type cables by using thin composite
Cu/$Gd_2$O$_3$ and Cu/$Gd_2$O$_2$S tapes produced by Hyper Tech Research, Inc.
The tape can be either wrapped around the cable, placed on the cable wide faces
under the insulation, and/or inserted as a core. Wire samples outfitted with
these high-$C_p$ ribbons, or tapes, were prepared and tested at FNAL for their
Minimum Quench Energy (MQE). At 90%I$_c$ and 15 T, the average gain of MQE of
the Nb$_3$Sn wire soldered to the Cu/$Gd_2$O$_2$S 55 micrometer thick ribbon
was 2.5, and further increased at larger transport currents.


title: A note on occur-check (extended report)

abstract:
  We weaken the notion of "not subject to occur-check" (NSTO), on which most
known results on avoiding the occur-check in logic programming are based. NSTO
means that unification is performed only on such pairs of atoms for which the
occur-check never succeeds in any run of a nondeterministic unification
algorithm. Here we show that "any run" can be weakened to "some run". We
present some related sufficient conditions under which the occur-check may be
safely omitted. We show examples for which the proposed approach provides more
general results than the approaches based on well-moded and nicely moded
programs (this includes cases to which the latter approaches are inapplicable).
We additionally present a sufficient condition based on NSTO, working for
arbitrary selection rules.


title:
Realising a one-dimensional topological gauge theory in an optically
  dressed Bose-Einstein condensate

abstract:
  Topological gauge theories describe the low-energy properties of certain
strongly correlated quantum systems through effective weakly interacting
models. A prime example is the Chern-Simons theory of fractional quantum Hall
states, where anyonic excitations emerge from the coupling between weakly
interacting matter particles and a density-dependent gauge field. While in
traditional solid-state platforms such gauge theories are only convenient
theoretical constructions, engineered quantum systems enable their direct
implementation and provide a fertile playground to investigate their
phenomenology without the need for strong interactions. Here, we report the
first quantum simulation of a topological gauge theory by realising a
one-dimensional reduction of the Chern-Simons theory (the chiral BF theory) in
a Bose-Einstein condensate. Using the local conservation laws of the theory we
eliminate the gauge degrees of freedom in favour of chiral matter interactions,
which we engineer by synthesising optically dressed atomic states with
momentum-dependent scattering properties. This allows us to reveal the key
properties of the chiral BF theory: the formation of chiral solitons and the
emergence of an electric field generated by the system itself. Our results
expand the scope of quantum simulation to topological gauge theories and pave
the way towards implementing analogous gauge theories in higher dimensions.

categories: cond-mat.quant-gas cond-mat.str-el nlin.PS quant-ph


title:
Self-supervised Vision Transformers for Joint SAR-optical Representation
  Learning

abstract:
  Self-supervised learning (SSL) has attracted much interest in remote sensing
and earth observation due to its ability to learn task-agnostic representations
without human annotation. While most of the existing SSL works in remote
sensing utilize ConvNet backbones and focus on a single modality, we explore
the potential of vision transformers (ViTs) for joint SAR-optical
representation learning. Based on DINO, a state-of-the-art SSL algorithm that
distills knowledge from two augmented views of an input image, we combine SAR
and optical imagery by concatenating all channels to a unified input.
Subsequently, we randomly mask out channels of one modality as a data
augmentation strategy. While training, the model gets fed optical-only,
SAR-only, and SAR-optical image pairs learning both inner- and intra-modality
representations. Experimental results employing the BigEarthNet-MM dataset
demonstrate the benefits of both, the ViT backbones and the proposed multimodal
SSL algorithm DINO-MM.


title: Contraction Analysis of Hopfield Neural Networks with Hebbian Learning

abstract:
  Motivated by advances in neuroscience and machine learning, this paper is
concerned with the modeling and analysis of Hopfield neural networks with
dynamic recurrent connections undergoing Hebbian learning. To capture the
synaptic sparsity of neural circuits, we propose a low dimensional formulation
for the model and then characterize its key dynamical properties. First, we
give a biologically-inspired forward invariance result. Then, we give
sufficient conditions for the non-Euclidean contractivity of the model. Our
contraction analysis leads to stability and robustness of time-varying
trajectories -- for networks with both excitatory and inhibitory synapses
governed by both Hebbian and anti-Hebbian rules. Our proposed contractivity
test is based upon biologically meaningful quantities, e.g., neural and
synaptic decay rate, maximum out-degree, and the maximum synaptic strength.
Finally, we show that the model satisfies Dale's principle. The effectiveness
of our results is illustrated via a numerical example.


title: Expanding the Materials Search Space for Multivalent Cathodes

abstract:
  Multivalent batteries are an energy storage technology with the potential to
surpass lithium-ion batteries, however their performance has been limited by
the low voltages and poor solid-state ionic mobility of available cathodes. A
computational screening approach to identify high-performance multivalent
intercalation cathodes among materials that do not contain the working ion of
interest has been developed which greatly expands the search space that can be
considered for materials discovery. This approach has been applied to magnesium
cathodes as a proof of concept and four resulting candidate materials (NASICON
V$_2$(PO$_4$)$_3$, birnessite NaMn$_4$O$_8$, tavorite MnPO$_4$F, and spinel
MnO$_2$) are discussed in further detail. In examining the ion migration
environment and associated Mg$^{2+}$ migration energy in these materials, local
energy maxima are found to correspond with pathway positions where Mg$^{2+}$
passes through a plane of anion atoms. While previous works have established
the influence of local coordination on multivalent ion mobility, these results
suggest that considering both the type of local bonding environment as well as
available free volume for the mobile ion along its migration pathway can be
significant for improving solid-state mobility.


title:
Spin-orbit coupling controlled ground states in the double perovskite
  iridates A2BIrO6 (A = Ba, Sr; B = Lu, Sc)

abstract:
  Iridates with the 5$d^4$ electronic configuration have attracted recent
interest due to reports of magnetically-ordered ground states despite
longstanding expectations that their strong spin-orbit coupling would generate
a $J = 0$ electronic ground state for each Ir$^{5+}$ ion. The major focus of
prior research has been on the double perovskite iridates Ba$_2$YIrO$_6$ and
Sr$_2$YIrO$_6$, where the nature of the ground states (i.e. ordered vs
non-magnetic) is still controversial. Here we present neutron powder
diffraction, high energy resolution fluorescence detected x-ray absorption
spectroscopy (HERFD-XAS), resonant inelastic x-ray scattering (RIXS), magnetic
susceptibility, and muon spin relaxation data on the related double perovskite
iridates Ba$_2$LuIrO$_6$, Sr$_2$LuIrO$_6$, Ba$_2$ScIrO$_6$, and Sr$_2$ScIrO$_6$
that enable us to gain a general understanding of the electronic and magnetic
properties for this family of materials. Our HERFD-XAS and RIXS measurements
establish $J = 0$ electronic ground states for the Ir$^{5+}$ ions in all cases,
with similar values for Hund's coupling $J_{\rm H}$ and the spin-orbit coupling
constant $\lambda_{\rm SOC}$. Our bulk susceptibility and muon spin relaxation
data find no evidence for long-range magnetic order or spin freezing, but they
do reveal weak paramagnetic signals that are consistent with extrinsic origins.
Our results indicate that the large $\lambda_{\rm SOC}$ is the key driving
force behind the electronic and magnetic ground states realized in the 5$d^4$
double perovskite iridates, which agrees well with conventional wisdom.


title:
Synchronous observation of Bell nonlocality and state-dependent
  Kochen-Specker contextuality

abstract:
  Bell nonlocality and Kochen-Specker contextuality are two remarkable
nonclassical features of quantum theory, related to strong correlations between
outcomes of measurements performed on quantum systems. Both phenomena can be
witnessed by the violation of certain inequalities, the simplest and most
important of which are the Clauser-Horne-Shimony-Holt (CHSH) and the
Klyachko-Can-Binicio\v{g}lu-Shumovski (KCBS), for Bell nonlocality and
Kochen-Specker contextuality, respectively. It has been shown that, using the
most common interpretation of Bell scenarios, quantum systems cannot violate
both inequalities concomitantly, thus suggesting a monogamous relation between
the two phenomena. In this Letter, we show that the joint consideration of the
CHSH and KCBS inequalities naturally calls for the so-called generalized Bell
scenarios, which, contrary to the previous results, allows for joint violation
of them. A photonic experiment thus tests the synchronous violation of both
CHSH and KCBS inequalities. Our results agree with the theoretical predictions,
thereby providing experimental proof of the coexistence of Bell nonlocality and
Kochen-Specker contextuality in the simplest scenario, and shed new light for
further explorations of nonclassical features of quantum systems.


title:
Encoding a one-dimensional topological gauge theory in a Raman-coupled
  Bose-Einstein condensate

abstract:
  Topological gauge theories provide powerful effective descriptions of certain
strongly correlated systems, a prime example being the Chern-Simons gauge
theory of fractional quantum Hall states. Engineering topological gauge
theories in controlled quantum systems is of both conceptual and practical
importance, as it would provide access to systems with exotic excitations such
as anyons without the need for strong correlations. Here, we discuss a scheme
to engineer the chiral BF theory, a minimal model of a topological gauge theory
corresponding to a one-dimensional reduction of the Chern-Simons theory, with
ultracold atoms. Using the local conservation laws of the theory, we encode its
quantum Hamitonian into an ultracold quantum gas with chiral interactions.
Building on a seminal proposal by Edmonds et al. (Phys. Rev. Lett. 110, 085301
(2013)), we show how to implement it in a Raman-coupled Bose-Einstein
condensate with imbalanced scattering lengths, as we have recently realized
experimentally. We discuss the properties of the chiral condensate from a gauge
theory perspective, and assess the validity of the effective quantum
description for accessible experimental parameters via numerical simulations.
Our approach lays the foundation for realizing topological gauge theories in
higher dimensions with Bose-Einstein condensates.


title:
Deformation of a magnetic liquid drop and unsteady flow inside and
  outside it in a non-stationary magnetic field

abstract:
  Small steady-state deformational oscillations of a drop of a viscous magnetic
liquid in a non-stationary uniform magnetic field are theoretically
investigated for low Reynolds numbers. The drop is suspended in another viscous
magnetic liquid immiscible with the former. The non-stationary magnetic field
causes flow inside and outside the drop. The inertia is taken into account by
regarding the flow as essentially unsteady. The variation of the magnetic field
is so slow that the approximation of quasi-stationary magnetic field may be
used.


title:
The relative contributions of TRIP and TWIP to strength in fine grained
  medium-Mn steels

abstract:
  A medium Mn steel of composition Fe-4.8Mn-2.8Al-1.5Si-0.51C (wt.\%) was
processed to obtain two different microstructures representing two different
approaches in the hot rolling mill, resulting in equiaxed vs. a mixed equiaxed
and lamellar microstructures. Both were found to exhibit a simultaneous
TWIP$+$TRIP plasticity enhancing mechanism where deformation twins and
$\alpha'$-martensite formed independently of twinning with strain. Interrupted
tensile tests were conducted in order to investigate the differences in
deformation structures between the two microstructures. A constitutive model
was used to find that, surprisingly, twinning contributed relatively little to
the strength of the alloy, chiefly due to the fine initial slip lengths that
then gave rise to relatively little opportunity for work hardening by grain
subdivision. Nevertheless, with lower high-cost alloying additions than
equivalent Dual Phase steels (2-3 wt\% Mn) and greater ductility, medium-Mn
TWIP$+$TRIP steels still represent an attractive area for future development.


title: Random Similarity Forests

abstract:
  The wealth of data being gathered about humans and their surroundings drives
new machine learning applications in various fields. Consequently, more and
more often, classifiers are trained using not only numerical data but also
complex data objects. For example, multi-omics analyses attempt to combine
numerical descriptions with distributions, time series data, discrete
sequences, and graphs. Such integration of data from different domains requires
either omitting some of the data, creating separate models for different
formats, or simplifying some of the data to adhere to a shared scale and
format, all of which can hinder predictive performance. In this paper, we
propose a classification method capable of handling datasets with features of
arbitrary data types while retaining each feature's characteristic. The
proposed algorithm, called Random Similarity Forest, uses multiple
domain-specific distance measures to combine the predictive performance of
Random Forests with the flexibility of Similarity Forests. We show that Random
Similarity Forests are on par with Random Forests on numerical data and
outperform them on datasets from complex or mixed data domains. Our results
highlight the applicability of Random Similarity Forests to noisy, multi-source
datasets that are becoming ubiquitous in high-impact life science projects.


title: Analysis of the ALMA Cycle 8 Distributed Peer Review Process

abstract:
  In response to the challenges presented by high reviewer workloads in
traditional panel reviews and increasing numbers of submitted proposals, ALMA
implemented distributed peer review to assess the majority of proposals
submitted to the Cycle 8 Main Call. In this paper, we present an analysis of
this review process. Over 1000 reviewers participated in the process to review
1497 proposals, making it the largest implementation of distributed peer review
to date in astronomy, and marking the first time this process has been used to
award the majority of observing time at an observatory. We describe the process
to assign proposals to reviewers, analyze the nearly 15,000 ranks and comments
submitted by reviewers to identify any trends and systematics, and gather
feedback on the process from reviewers and Principal Investigators (PIs)
through surveys. Approximately 90% of the proposal assignments were aligned
with the expertise of the reviewer, as measured both by the expertise keywords
provided by the reviewers and the reviewers' self-assessment of their expertise
on their assigned proposals. PIs rated 73% of the individual review comments as
helpful, and even though the reviewers had a broad range of experience levels,
PIs rated the quality of the comments received from students and senior
researchers similarly. The primary concerns raised by PIs were the quality of
some reviewer comments and high dispersions in the ranks. The ranks and
comments are correlated with various demographics to identify the main areas in
which the review process can be improved in future cycles.


title:
A Non-Local Quasi-Linear Ground State Representation and Criticality
  Theory

abstract:
  We study energy functionals associated with non-local quasi-linear
Schr\"odinger operators, and develop a ground state representation. Our main
focus is on infinite graphs but we also consider non-local quasi-linear
Schr\"odinger operators in the Euclidean space. Using the representation, we
develop a criticality theory for quasi-linear Schr\"odinger operators on
general weighted graphs, and show characterisations for a Hardy inequality to
hold true. As an application, we show a Liouville comparison principle on
graphs.


title:
Magnetoquantum Oscillations in the Specific Heat of a Topological Kondo
  Insulator

abstract:
  Surprisingly, magnetoquantum oscillations (MQO) characteristic of a metal
with a Fermi surface have been observed in measurements of the topological
Kondo insulator SmB6. As these MQO have only been observed in measurements of
magnetic torque (dHvA) and not in measurements of magnetoresistance (SdH), a
debate has arisen as to whether the MQO are an extrinsic effect arising from
rare-earth impurities, defects, and/or aluminum inclusions or an intrinsic
effect revealing the existence of charge-neutral excitations. We report here
the first observation of magnetoquantum oscillations in the low-temperature
specific heat of SmB6. The observed frequencies and their angular dependence
for these flux-grown samples are consistent with previous results based on
magnetic torque for SmB6 but the inferred effective masses are significantly
larger than previously reported. Such oscillations can only be observed if the
MQO are of bulk thermodynamic origin; the measured magnetic-field dependent
oscillation amplitude and effective mass allow us to rule out suggestions of an
extrinsic, aluminium inclusion-based origin for the MQO.


title: Improving Few-Shot Part Segmentation using Coarse Supervision

abstract:
  A significant bottleneck in training deep networks for part segmentation is
the cost of obtaining detailed annotations. We propose a framework to exploit
coarse labels such as figure-ground masks and keypoint locations that are
readily available for some categories to improve part segmentation models. A
key challenge is that these annotations were collected for different tasks and
with different labeling styles and cannot be readily mapped to the part labels.
To this end, we propose to jointly learn the dependencies between labeling
styles and the part segmentation model, allowing us to utilize supervision from
diverse labels. To evaluate our approach we develop a benchmark on the
Caltech-UCSD birds and OID Aircraft dataset. Our approach outperforms baselines
based on multi-task learning, semi-supervised learning, and competitive methods
relying on loss functions manually designed to exploit sparse-supervision.