University of Guadalajara
Departamento de Física (CUCEI)
Andrei Klimov
University of Guadalajara | UDG · Departamento de Física (CUCEI)
Publications 269
Continuos and discrete phase-space methods. Discrete quantum systems. Quantum optical models.
Foundations of Quantum Mechanics
Local sampling of the SU(1,1) Wigner function
Nicolas Fabre
Gerd Leuchs
L. L. Sanchez-Soto
Despite the indisputable merits of the Wigner phase-space formulation, it has not been widely explored for systems with SU(1,1) symmetry, as a simple operational definition of the Wigner function has proved elusive in this case. We capitalize on the unique properties of the parity operator, to derive in a consistent way a \emph{bona fide} SU(1,1) W...
The Macroscopic Evolution in the Measurement Space
C. Muñoz
We analyze the dynamics of N-qubit systems in the measurement space under the action of symmetric Hamiltonians. We show that the evolution of the discrete distribution function, representing the global properties of multipartite states, becomes quasicontinuous in the macroscopic limit N ≫ 1. The shorttime dynamics can be approximately described as...
From polarization multipoles to higher-order coherences
Aaron Z. Goldberg
Hubet de Guise
We demonstrate that the multipoles associated with the density matrix are truly observable quantities that can be unambiguously determined from intensity moments. Given their correct transformation properties, these multipoles are the natural variables to deal with a number of problems in the quantum domain. In the case of polarization, the moments...
Random Majorana Constellations
Jose Luis Romero Hervás
Angel S. Sanz
Even the most classical states are still governed by quantum theory. A fantastic array of physical systems can be described by their Majorana constellations of points on the surface of a sphere, where concentrated constellations and highly symmetric distributions correspond to the least and most quantum states, respectively. If these points are cho...
Dual form of the phase-space classical simulation problem in quantum optics
A A Semenov
In quantum optics, nonclassicality of quantum states is commonly associated with negativities of phase-space quasiprobability distributions.We argue that the impossibility of any classical simulations with phase-space functions is a necessary and sufficient condition of nonclassicality. The problem of such phase-space classical simulations for part...
Hubert de Guise
Semi-Classical Discretization and Long-Time Evolution of Variable Spin Systems
Giovani E. Morales-Hernández
Juan C. Castellanos
José Luis Romero
We apply the semi-classical limit of the generalized $SO(3)$ map for representation of variable-spin systems in a four-dimensional symplectic manifold and approximate their evolution terms of effective classical dynamics on $T^{\ast }\mathcal{S}_{2}$. Using the asymptotic form of the star-product, we manage to "quantize" one of the classical dynami...
MUB-like structures and tomographic reconstruction for N-ququart systems
Juan Díaz-Guevara
Isabel Sainz
We construct an informationally complete set of mutually unbiased - like bases for N ququarts. These bases are used in an explicit tomographic protocol which performance is analyzed by estimating quadratic errors and compared to other reconstruction schemes.
Truncated Wigner approximation as a non-positive Kraus map
We show that the Truncated Wigner Approximation developed in the flat phase-space is mapped into a Lindblad-type evolution with an indefinite metric in the space of linear operators. As a result, the classically evolved Wigner function corresponds to a non-positive operator $\hat{R}(t)$, which does not describe a physical state. The rate of appeara...
Effective and efficient resonant transitions in periodically modulated quantum systems
Andres Garcia
We analyse periodically modulated quantum systems with $SU(2)$ and $SU(1,1)$ symmetries. Transforming the Hamiltonian into the Floquet representation we apply the Lie transformation method, which allows us to classify all effective resonant transitions emerging in time-dependent systems. In the case of a single periodically perturbed system, we pro...
Macroscopic features of quantum fluctuations in large N qubit system
We introduce a discrete Q-function of N qubit system projected into the space of symmetric measurements as a tool for analyzing general properties of quantum systems in the macroscopic limit. For known states the projected Q-function helps to visualize the results of collective measurements, and for unknown states it can be approximately reconstruc...
Juan Jesús Díaz Guevara
We apply the semi-classical limit of the generalized SO(3) map for representation of variable-spin systems in a four-dimensional symplectic manifold and approximate their evolution terms of effective classical dynamics on T*S2. Using the asymptotic form of the star-product, we manage to "quantize" one of the classical dynamic variables and introduc...
Macroscopic stability of cluster states under local transformations
Mario Gaeta
We prove that all macroscopic properties of the N -qubit cluster state are asymptotically invariant under local transformations in the limit N ≫ 1, and can be described by a distribution function similar to that of the completely mixed state.
Rotation sensing at the ultimate limit
Conventional classical sensors are approaching their maximum sensitivity levels in many areas. Yet these levels are still far from the ultimate limits dictated by quantum mechanics. Quantum sensors promise a substantial step ahead by taking advantage of the salient sensitivity of quantum states to the environment. Here, we focus on sensing rotation...
We analyze periodically modulated quantum systems with SU(2) and SU(1,1) symmetries. Transforming the Hamiltonian into the Floquet representation we apply the Lie transformation method, which allows us to classify all effective resonant transitions emerging in time-dependent systems. In the case of a single periodically perturbed system, we propose...
Isospectral mapping for quantum systems with energy point spectra to polynomial quantum harmonic oscillators
Ole Steuernagel
We show that a polynomial Hˆ(N) of degree N of a harmonic oscillator hamiltonian allows us to devise a fully solvable continuous quantum system for which the first N discrete energy eigenvalues can be chosen at will. In general such a choice leads to a re-ordering of the associated energy eigenfunctions of Hˆ such that the number of their nodes doe...
SU(1,1) covariant s-parametrized maps
Ulrich Seyfarth
We propose a practical recipe to compute the s -parametrized maps for systems with SU(1, 1) symmetry using a connection between the Q- and P- symbols through the action of an operator invariant under the group. This establishes equivalence relations between s -parametrized SU(1, 1)-covariant maps. The particular case of the self-dual (Wigner) phase...
Long-time semiclassical evolution of spinlike systems from Majorana sampling
Iván F. Valtierra
We propose an approach to the analysis of the semiclassical evolution of spinlike systems. We show that an appropriate discretization of distributions in classical phase space (in this case the two-dimensional sphere S2) allows us to describe long-time dynamics (including the Schrödinger cat times) in terms of classical trajectories, both in stable...
SU(1,1)$ covariant $s$-parametrized maps
We propose a practical recipe to compute the ${s}$-parametrized maps for systems with $SU(1,1)$ symmetry using a connection between the ${Q}$ and ${P} $ symbols through the action of an operator invariant under the group. The particular case of the self-dual (Wigner) phase-space functions, defined on the upper sheet of the two-sheet hyperboloid (or...
Conventional classical sensors are approaching their maximum sensitivity levels in many areas. Yet these levels still are far from the ultimate limits dictated by quantum mechanics. Quantum sensors promise a substantial step ahead by taking advantage of the salient sensitivity of quantum states to the environment. Here, we focus on sensing rotation...
Extremal quantum states
Markus Grassl
The striking differences between quantum and classical systems predicate disruptive quantum technologies. We peruse quantumness from a variety of viewpoints, concentrating on phase-space formulations because they can be applied beyond particular symmetry groups. The symmetry-transcending properties of the Husimi Q function make it our basic tool. I...
Quantum concepts in optical polarization
Pablo de la Hoz
Gunnar Björk
We comprehensively review the quantum theory of the polarization properties of light. In classical optics, these traits are characterized by the Stokes parameters, which can be geometrically interpreted using the Poincaré sphere. Remarkably, these Stokes parameters can also be applied to the quantum world, but then important differences emerge: now...
Gunnar Bjork
We comprehensively review the quantum theory of the polarization properties of light. In classical optics, these traits are characterized by the Stokes parameters, which can be geometrically interpreted using the Poincar\'e sphere. Remarkably, these Stokes parameters can also be applied to the quantum world, but then important differences emerge: n...
The striking differences between quantum and classical systems predicate disruptive quantum technologies. We peruse quantumness from a variety of viewpoints, concentrating on phase-space formulations because they can be applied beyond particular symmetry groups. The symmetry-transcending properties of the Husimi $Q$ function make it our basic tool....
Dual problem of nonclassicality
A. A. Semenov
We show that nonclassicality of phase-space quasi-probability distributions is tied to violations of principles of physical reality in device-dependent scenarios. In this context, the nonclassicality problem has its dual form expressed as a device-dependent analog of Bell inequalities. This approach is applicable even to systems with only one spati...
Wigner function for SU(1,1)
H. de Guise
In spite of their potential usefulness, Wigner functions for systems with SU(1,1) symmetry have not been explored thus far. We address this problem from a physically-motivated perspective, with an eye towards applications in modern metrology. Starting from two independent modes, and after getting rid of the irrelevant degrees of freedom, we derive...
Truncated Wigner approximation as non-positive Kraus map
We show that the Truncated Wigner Approximation developed in the flat phase-space is mapped into a Lindblad-type evolution with an indefinite metric in the space of linear operators. As a result, the classically evolved Wigner function corresponds to a non-positive operator $\hat{R}(t)$ , which does not describe a physical state. The rate of appear...
Macroscopic approach to N-qudit systems
Quasiprobability currents on the sphere
Ivan Valtierra
We present analytic expressions for the s-parametrized currents on the sphere for both unitary and dissipative evolutions. We examine the spatial distribution of the flow generated by these currents for quadratic Hamiltonians. The results are applied for the study of the quantum dissipative dynamics of the time-honored Kerr and Lipkin models, explo...
We develop a general scheme for an analysis of macroscopic qudit systems: a) introduce a set of collective observables, which characterizes the macroscopic properties of qudits in an optimal way; b) construct projected $\tilde{Q}$-functions for $N$ qudit systems, containing full macroscopic information; c) propose a collective tomographic protocol...
We present analytic expressions for the $s$-parametrized currents on the sphere for both unitary and dissipative evolutions. We examine the spatial distribution of the flow generated by these currents for quadratic Hamiltonians. The results are applied for the study of the quantum dissipative dynamics of the time-honored Kerr and Lipkin models, exp...
In spite of their potential usefulness, Wigner functions for systems with SU(1,1) dynamical symmetry have not been explored thus far. We address this problem from a physically-motivated perspective, with an eye towards applications in modern metrology. Starting from two independent modes, and after getting rid of the irrelevant degrees of freedom,...
Deterministic entanglement extraction
Luis Roa
Ariana Muñoz
We propose a scheme for a deterministic extraction of entanglement by means of a reduction process involving local von Neumann measurements. In an example of a tripartite system, we show that by choosing appropriate measurement bases for a given qubit, one can map an initial three-qubit state into outcome pure bipartite states with the same amount...
Correspondence rules for Wigner functions over SU(3)/U(2)
Alex Clesio Nunes Martins
We present results on the * product for SU(3) Wigner functions over SU(3)/U(2). In particular, we present a form of the so-called correspondence rules, which provide a differential form of the * product A*B and A*B when A is an su(3) generator. For the su(3) Wigner map, these rules must contain second order derivatives and thus substantially differ...
The Wigner flow on the sphere
Popo Yang
We derive a continuity equation for the evolution of the SU(2) Wigner function under nonlinear Kerr evolution. We give explicit expressions for the resulting quantum Wigner current, and discuss the appearance of the classical limit. We show that the global structure of the quantum current significantly differs from the classical one, which is clear...
P. Yang
Picturing quantum phase transitions
M. Gaeta
R. Gomez
We discuss the quantum phase transitions (QPT) in N-spin chains from the point of view of collective observables. We show that the measurement space representation is a convenient tool for the analysis of phase transitions, allowing the determination of an appropriate set of macroscopic order parameters (for a given Hamiltonian). Quantum correlatio...
Tomography from collective measurements
We discuss the tomography of N-qubit states using collective measurements. The method is exact for symmetric states, whereas for not completely symmetric states the information accessible can be arranged as a mixture of irreducible SU(2) blocks. For the fully symmetric sector, the reconstruction protocol can be reduced to projections onto a canonic...
We discuss the tomography of $N$-qubit states using collective measurements. The method is exact for symmetric states, whereas for not completely symmetric states the information accessible can be arranged as a mixture of irreducible SU(2) blocks. For the fully symmetric sector, the reconstruction protocol can be reduced to projections onto a canon...
Equilibration and thermalization in the measurement space
We discuss equilibration and thermalization processes in N-spin systems from the point of view of collective observables. We show that the measurement space approach is a convenient tool for the analysis of these effects, allowing one to observe the emergence of irreversibility even for a relatively small numbers of particles. Equilibrating dynamic...
MUB tomography performance under influence of systematic errors
We propose a method for accounting the simplest type of systematic errors in the mutually unbiased bases (MUB) tomography, emerging due to an imperfect (non-orthogonal) preparation of measurement bases. The present approach allows to analyze analytically the performance of MUB tomography in finite systems of an arbitrary (prime) dimension. We compa...
Generalized SU (2) covariant Wigner functions and some of their applications
We survey some applications of SU(2) covariant maps to the phase space quantum mechanics of systems with fixed or variable spin. A generalization to SU(3) symmetry is also briefly discussed in framework of the axiomatic Stratonovich–Weyl formulation.
Optimal lossy quantum interferometry in phase space
Marcin Zwierz
Sascha Wallentowitz
Konrad Banaszek
We analyse the phase space representation of the optimal measurement of a phase shift in an interferometer with equal photon loss in both its arms. In the local phase estimation scenario with a fixed number of photons, we identify features of the spin Wigner function that warrant sub-shot noise precision, and discuss their sensitivity to losses. We...
TWA versus semiclassical unitary approximation for spin-like systems
We analyze the stable and unstable evolution of spin-like systems in the framework of the Truncated Wigner and Unitary Approximations, and test the dependence of the time scale where the classical evolution determines the dynamics of a quantum system on the semiclassical parameter.
Discrete phase-space structures and Wigner functions for N qubits
We further elaborate on a phase-space picture for a system of N qubits and explore the structures compatible with the notion of unbiasedness. These consist of bundles of discrete curves satisfying certain additional properties and different entanglement properties. We discuss the construction of discrete covariant Wigner functions for these bundles...
Symplectic approach to construction of cyclic and non-cyclic sets of mutually unbiased bases
A. Garcia
We formulate the construction of cyclic and non-cyclic complete sets of mutually unbiased bases, corresponding to the underlyining field and semifield structures, in the framework of the symplectic approach.
Bi-orthogonal mutually unbiased bases for N-qubit systems
Juan J Díaz
We have developed a general method for constructing a set of non-orthogonal bases with equal separations between all different basis' states for N-qubit systems. Using these bases we derive an explicit expression for the optimal tomography in non-orthogonal bases and discuss the amount of non-classical resources required for the bases preparation a...
Quantum metrology at the limit with extremal Majorana constellations
Frederic Bouchard
G. Bjork
Quantum metrology allows for a tremendous boost in the accuracy of measurement of diverse physical parameters. The estimation of a rotation constitutes a remarkable example of this quantum-enhanced precision, and it has been demonstrated in, e.g., magnetometry and polarimetry. When the rotation axis is known, NOON states are optimal for this task,...
Error estimation in the direct state tomography
We show that reformulating the Direct State Tomography (DST) protocol in terms of projections into a set of non-orthogonal bases one can perform an accuracy analysis of DST in a similar way as in the standard projection-based reconstruction schemes. i.e. in terms of the Hilbert-Schmidt distance between estimated and true states. This allows us to d...
Gaussianity and localization of N -qubit states
We analyze collective properties of N-qubit states. In particular, we exhaustively discuss the localization aspect of distributions in the measurement space and introduce the concept of Gaussian states in the macroscopic limit. The effect of local shifts on the localization and Gaussianity is analyzed.
Correlation transfer in large-spin chains
It is shown that transient spin-spin correlations in one-dimensional spin S>>1 chain can be enhanced for initially factorized and individually squeezed spin states. Such correlation transfer form "internal" to "external" degrees of freedom can be well described by using a semiclassical phase-space approach.
Parsing polarization squeezing into Fock layers
Christian R. Müller
Lars S. Madsen
Ulrik L. Andersen
We investigate polarization squeezing in squeezed coherent states with varying coherent amplitudes. In contrast to the traditional characterization based on the full Stokes parameters, we experimentally determine the Stokes vector of each excitation subspace separately. Only for states with a fixed photon number do the methods coincide; when the ph...
Discrete phase-space mappings, tomographic condition and permutation invariance
We analyze different families of discrete maps\ in the N-qubit systems in the context of the permutation invariance. We prove that the tomographic condition imposed on the self-dual (Wigner) map is incompatible with the requirement of the invariance under particle permutations, which makes it impossible to project the Wootters-like Wigner function...
Parsing Squeezed Light into Polarization Manifolds
L. S. Madsen
We investigate polarization squeezing in squeezed coherent states with varying coherent amplitudes. In contrast to the traditional characterization based on the full Stokes parameters, we experimentally determine the Stokes vector of each excitation manifold separately. Only for states with a fixed photon number do the methods coincide; when the ph...
1751-8121 48 21 215303
Katsumi Tomatani
Extremal quantum states and their Majorana constellations
G. Björk
The characterization of quantum polarization of light requires knowledge of all the moments of the Stokes variables, which are appropriately encoded in the multipole expansion of the density matrix. We look into the cumulative distribution of those multipoles and work out the corresponding extremal pure states. We find that SU(2) coherent states ar...
Quantum tomography via Non-orthogonal basis and weak values
J.J. Díaz
Using a relation between a biorthogonal set of equiseparable bases and the weak values of the density matrix we derive an explicit formula for its tomographic reconstruction completely analogous to the standard mutually unbiased bases expansion.
Semiclassical dynamics of the resonant Dicke model in a strongly non-linear regime
Sergei Chumakov
We study semiclassical dynamics of the resonant Dicke model under the rotation wave approximation (RWA) for initial vacuum field state and all excited atoms in the asymptotic limit of a large number of atoms. We develop a new approach for description of the evolution of such unstable states by combining semiclassical and quantum approaches.
Classical polarization multipoles: paraxial versus nonparaxial
G Björk
H de Guise
We discuss the polarization of paraxial and nonparaxial classical light fields by resorting to a multipole expansion of the corresponding polarization matrix. It turns out that only a dipolar term contributes when one considers SU(2) (paraxial) or SU(3) (nonparaxial) as fundamental symmetries. In this latter case, one can alternatively expand in SU...
Semiclassical phase-space dynamics of compound quantum systems: SU(2) covariant approach
The semiclassical evolution of the generalized SU(2) Wigner function for quantum systems with a variable number of excitations is discussed in detail. It is shown that in the framework of the Liouvillian approach quantum dynamics can be approximately described in terms of classical trajectories on an appropriate four-dimensional symplectic manifold...
Semiclassical dynamics of a rigid rotor: SO(3) covariant approach
A semi-classical analysis of the quantum rigid-rotor motion based on a phase-space description of the rotation in terms of a SO(3) covariant Wigner-like distribution is presented. The results are applied to the description of the intense-field alignment of an anisotropically polarizable molecule with high rotational excitation.
Extremal Polarization States of Light: From Classical to Quantum
The full characterization of quantum polarization of light requires the knowledge of all the moments of the Stokes variables, which are appropriately encoded in the multipole expansion of the density matrix. We look into the cumulative distribution of those multipoles and work out the corresponding extremal states. We find that SU(2) coherent state...
Erratum: A measure for maximum similarity between outcome states
Alejandra Maldonado-Trapp
Original article: EPL, 109 (2015) 40001.
A measure for maximum similarity between outcome states
We propose a measure to quantify correlations in a bipartite quantum system of two quibits by assessing the minimum difference between outcome states of a subsystem by performing a local measurement on the other subsystem. This maximum similarity measure is a monotone function of the concurrence for pure states of two qubits; for mixed states it ac...
Unitarily inequivalent mutually unbiased bases for n qubits
Arun Sehrawat
The standard construction of complete sets of mutually unbiased bases (MUBs) in prime power dimensions is based on the quadratic Gauss sums. We introduce complete MUB sets for three, four, and five qubits that are unitarily inequivalent to all existing MUB sets. These sets are constructed by using certain exponential sums, where the degree of the p...
Maximally Entangled States of Four Nonbinary Particles
Jay Lawrence
Systems of four nonbinary particles, each having three or more internal states, exhibit maximally entangled states that are inaccessible to four qubits. This breaks the pattern of two- and three-particle systems, in which the existing graph states are equally accessible to binary and nonbinary systems alike. We compare the entanglement properties o...
Unpolarized states and hidden polarization
We capitalize on a multipolar expansion of the polarisation density matrix, in which multipoles appear as successive moments of the Stokes variables. When all the multipoles up to a given order $K$ vanish, we can properly say that the state is $K$th-order unpolarized, as it lacks of polarization information to that order. First-order unpolarized st...
Discrete phase-space approach to mutually orthogonal Latin squares
Olivia Di Matteo
We show there is a natural connection between Latin squares and commutative sets of monomials defining geometric structures in finite phase-space of prime power dimensions. A complete set of such monomials defines a mutually unbiased basis (MUB) and may be associated with a complete set of mutually orthogonal Latin squares (MOLS). We translate some...
Classical distinguishability as an operational measure of polarization
We put forward an operational degree of polarization that can be extended in a natural way to fields whose wave fronts are not necessarily planar. This measure appears as a distance from a state to the set of all its polarization-transformed counterparts. By using the Hilbert-Schmidt metric, the resulting degree is a sum of two terms: one is the pu...
Macroscopic features of quantum fluctuations in large- N qubit systems
We introduce a discrete $Q$ function of an $N$-qubit system projected into the space of symmetric measurements as a tool for analyzing general properties of quantum systems in the macroscopic limit. For known states the projected $Q$ function helps to visualize the results of collective measurements, and for unknown states it can be approximately r...
Complete sets of mutually unbiased operators in n-qudit systems
A García
An explicit construction of all the possible sets of n commuting monomials for an n-qudit system as well as an algorithm for the determination of their factorization are given here. The results are applied for the generation of locally non-isomorphic mutually unbiased complete sets and their classification according to the separability properties....
Discording power of Hamiltonian interactions
Cristian Ignacio Jara Figueroa
We analyze the creation of quantum correlations in a two-qubit system, initially prepared in a classical state, when only one qubit is locally coupled to a bath through a Hamiltonian interaction. We argue that a substantial part of the generated correlations is related to the presence of virtual excitations in the qubit-bath subsystem. The appearan...
Publisher's Note: Quantum-state tomography for optical polarization with arbitrary photon numbers [Phys. Rev. A 89, 020101(R) (2014)]
DOI:https://doi.org/10.1103/PhysRevA.89.039906
Quantum correlations support probabilistic pure state cloning
Marcelo Alid-Vaccarezza
The probabilistic scheme for making two copies of two nonorthogonal pure states requires two auxiliary systems, one for copying and one for attempting to project onto the suitable subspace. The process is performed by means of a unitary-reduction scheme which allows having a success probability of cloning different from zero. The scheme becomes opt...
Nested Construction of Families of Complex Hadamard Matrices
D. Goyeneche
We present a new parametrization of families of complex Hadamard matrices stemming from the Fourier matrices in every prime power dimension. We connect continuous Abelian groups with families of complex Hadamard matrices and conjecture that the constructed families are maximal. Also, we derive new relations for complex Hadamard matrices in every pr...
Quantum-state tomography for optical polarization with arbitrary photon numbers
A scheme for quantum-state tomography is presented that can be performed for polarized light with an arbitrary photon-number distribution. The proposed method fills the gap between existing polarization-tomography schemes for single-photon states and for optical fields with very large photon numbers. It consists of an optical homodyne setup trigger...
Multipolar hierarchy of efficient quantum polarization measures
Y. -H. Kim
We advocate a simple multipole expansion of the polarisation density matrix. The resulting multipoles appear as successive moments of the Stokes variables and can be obtained from feasible measurements. In terms of these multipoles, we construct a whole hierarchy of measures that accurately assess higher-order polarization fluctuations.
Correlation power of Hamiltonian interactions
We analyze the appearance of quantum correlations of two qubits prepared in a classical state. One qubit is locally coupled to a bath through a Hamiltonian interaction. We find that the generated correlations is related to the presence of virtual excitations of qubit-bath interaction.
Macroscopility and Localization in the Measurement Space
The concepts of macroscopicity and localization for large quantum systems is discussed and analyzed in relation with the asymptotic evolution in the measurement space under action of random and chaotic Hamiltonians.
Orbital angular momentum from marginals of quadrature distributions
We set forth a method to analyze the orbital angular momentum of a light field. Instead of using the canonical formalism for the conjugate pair angle-angular momentum, we model this latter variable by the superposition of two independent harmonic oscillators along two orthogonal axes. By describing each oscillator by a standard Wigner function, we...
Sizing up entanglement in mutually unbiased bases with Fisher information
Jaroslav Rehacek
Zdenek Hradil
An efficient method for assessing the quality of quantum state tomography is developed. Special attention is paid to the tomography of multipartite systems in terms of unbiased measurements. Although the overall reconstruction errors of different sets of mutually unbiased bases are the same, differences appear when particular aspects of the measure...
Equidistant-state preparation
We propose a scheme for preparing a set of bases constituted by equidistant states of a quantum system in prime dimension starting with a single entangled system-ancilla state. The required quantum correlations between the involved systems as a function of the separability constant are analyzed. A comparative analysis of errors in tomographic recon...
Quantum versus classical polarization states: When multipoles count