Neutron Time Of Flight

The Neutron Time Of Flight (n-TOF) facility is a neutron spectrometer at CERN. It consists of a pulsed source, a flight path of 200 m length, and a detector systems. Neutron energies are deduced from the time of flight between source and detector; hence the name of the facility. The neutrons are produced by neutron spallation; by directing a pulsed beam of protons from the Proton Synchrotron (PS) towards a lead target about 300 neutrons expelled for each impact of a proton. The neutrons are slowed after being emitted, first by the lead target and afterwards by a slab containing water. This results in a wide range of neutron energies since some neutrons will slow down more than others when passing through the targets. Finally, the neutrons are ejected through the 200m long flight path before they arrive at an experimental area.


David E. Kaplan (physicist)

David Elazzar Kaplan is a theoretical particle physicist at the Johns Hopkins University.
Biography.
David E. Kaplan received his Bachelor of Science from the University of California at Berkeley in 1991, his Master's in Physics from the University of Washington in 1996 and PhD from the same institute under supervision of Ann Nelson in 1999. After postdoctoral positions at the University of Chicago, Argonne National Lab and the Stanford Linear Accelerator Center, he joined the faculty at Johns Hopkins in 2002.
His primary research interest is physics beyond the standard model, with a particular focus on the Higgs mechanism and potentially related physics such as supersymmetry, new forces, extra dimensions, and dark matter. He is also exploring connections between high energy physics and cosmology. He was selected as a Kavli Frontiers Fellow of the National Academy of Sciences, and an Alfred P. Sloan Fellow.
In 2011, Kaplan co-hosted season three of National Geographic Channel's "Known Universe" documentary series along with Sigrid Close, Andy Howell, Michael J. Massimino, and Steve Jacobs. Kaplan also produced (and starred in) the documentary "Particle Fever".


Daniel Friedan

Daniel Harry Friedan (born October 3, 1948) is an American theoretical physicist and one of three children of the feminist author and activist Betty Friedan. He is a professor at Rutgers University.
Biography.
Education and career.
Friedan earned his Ph.D. from the University of California, Berkeley in 1980 and was named a MacArthur Fellow in 1987.
In 1979, he showed that the equations of motions of string theory, which are generalizations of the Einstein equations of general relativity, emerge from the renormalization group equations for the two-dimensional field theory.
Friedan has worked in string theory and condensed matter theory, specializing in (1 + 1)-dimensional systems. His current research focuses on applications to quantum computers.
Friedan received the 2010 Lars Onsager Prize from the American Physical Society "for seminal work on the classification and characterization of two-dimensional unitary conformal field theories of critical states." He teaches at Rutgers University currently.
Personal life.
Daniel is married to an Icelandic physics teacher, Ragnheiður Guðmundsdóttir. They have two daughters and one son together.


Thomas J. Bowles (physicist)

Thomas Joseph (Tom) Bowles is an American nuclear physicist who works at the Los Alamos National Laboratory. He served as the Laboratory's Chief Science Officer from 2004 to 2006, and also was science advisor to New Mexico Governor Bill Richardson from 2006.
Bowles received his B.Sc. degree at the University of Colorado in 1973 and his Ph.D. at Princeton University in 1978. He joined the Physics Division at Los Alamos in 1979 and was named a Fellow of the Laboratory in 1994.
He was elected a Fellow of the American Physical Society in 1992 and awarded the M. A. Markov Prize by the Russian Academy of Sciences' Institute for Nuclear Research in 2003.


Thomas Gerald Pickavance

Thomas Gerald Pickavance (19 October 1915 – 12 November 1991) was a British nuclear physicist who was a leading authority on the design and use of particle accelerators. He was generally known as Gerry Pickavance.
Life and career.
He was born in St Helens, Lancashire, the son of estate agent William Pickavance and his wife Ethel and was educated at the University of Liverpool.
He worked on the development of the University of Liverpool cyclotron and carried out research with it on the Tube Alloys project during the Second World War. He was later responsible for the construction of the Harwell cyclotron and became leader of the Accelerator Group.
During his time at Harwell he led research into new accelerators, which led to the installation in 1957 of the 50 MeV proton linear accelerator and the 8 GeV Nimrod Proton Synchrotron at the new Rutherford High Energy Laboratory, of which he was appointed the first Director. He was later Director of the Nuclear Physics Division of the Science Research Council and Chairman of the European Committee on Future Accelerators.
In 1965 he was made a Commander of the Order of the British Empire and in 1976 elected a Fellow of the Royal Society. In 1979 he was awarded the Glazebrook Medal by the Institute of Physics.
He died in 1991. He had married Alice Boulton and had two sons and a daughter.


Sergio Fubini

Sergio Fubini (December 31, 1928 – January 6, 2005) was an Italian theoretical physicist. He was one of the pioneers of string theory. He was engaged in peace activism in the Middle East.
Biography.
Fubini was born in Turin. In 1938, he fled the country as a politically persecuted Jew to Switzerland. In 1945, he attended the Lycée in Turin, where he studied physics and in 1950 graduated "cum laude." Afterwards, he was an assistant in Turin. From 1954 to 1957, he was in the USA. From 1958 to 1967, he was at CERN in Geneva. In 1959, he became a professor for nuclear physics at University of Padua. In 1961, he became a professor for theoretical physics at University of Turin. From 1968 to 1973, he was at MIT, but taught summer courses in Turin. He went back to CERN in 1973 and was from 1971 to 1980 a member of the advisory board and had an important role in planning the Large Electron Positron Collider (LEP) as well as in discussions for the construction of the Middle East's Synchrotron, SESAME.
At MIT, he was with Gabriele Veneziano, Emilio Del Giudice and Paolo Di Vecchia at the center of an active school of theoretical physicist with close connections to Italy (with one of the Italian INFN and MIT financed "Bruno Rossi" exchange programs).
He and his co-workers did fundamental work in string theory.
Other well-known MIT colleagues at that time were Victor Weisskopf (who was recruited by Fubini to MIT), Steven Weinberg and Roman Jackiw.
From 1994 to 2001, he was a professor in Turin.
Fubini worked in the 1960s on current algebras and S-matrix theory (Regge trajectories among other things), in particular on their field-theoretical foundations.
In the 1970s, he was with his MIT colleagues and pupils Gabriele Veneziano, Emilio Del Giudice and Paolo Di Vecchia one of the pioneers of string theory (the team introduced the so-called DDF states).
He worked in the 1970s on other classical solutions of Yang–Mills equations and conformally invariant quantum field theory.
Fubini died in 2005 in Nyon. He married Marina Colombo in 1956 and had a daughter with her.
Honors.
Fubini received the Dannie Heineman Prize for Mathematical Physics in 1968 and received an honorary doctorate from the University of Heidelberg.


Raymond Herb

Raymond George Herb (January 22, 1908 – October 1, 1996) was an American professor of nuclear physics at the University of Wisconsin–Madison. He was known for building electrostatic accelerators. His work influenced the Manhattan Project, which built the first nuclear weapons. In 1960, the University of Sao Paulo awarded him an honorary doctorate. He won the Bonner Prize in 1968. He started a company called NEC that manufactures electrostatic accelerators. He was also a member of the National Academy of Sciences.
University of Wisconsin now holds a seminar series in his memory.


Carlo Marangoni

Carlo Giuseppe Matteo Marangoni (29 April 1840 – 14 April 1925) was an Italian physicist.
Biography.
Marangoni graduated in 1865 from the University of Pavia under the supervision of Giovanni Cantoni with a dissertation entitled "" ("On the spreading of liquid droplets").
He then moved to Florence where he first worked at the "Museo di Fisica" (1866) and later at the Liceo Dante (1870), where he held the position of High School Physics Teacher for 45 years until retirement in 1916.
He primarily studied surface phenomena in liquids, and the Marangoni effect and the Marangoni number are named after him. He also contributed to meteorology and invented a "Nefoscopio" to observe clouds.
Aspirator and Compressor.
Marangoni simplified the aspirator for the measurement of gas. A common flaw in aspirator were inaccurate measurements caused by ascending of air or gas through descending liquid. The perfected device uses a couple of vessels attached to a fixed horizontal shaft, "FE", which rests on two erect supports. The shaft has various passages which conducts the functions of the taps. The water of the above receptacle releases into the bottom receptacle by passage "A", and through the tube, "BC", issuing at the lowest extremity at "C". The air within the bottom vessel is omitted by the passage "DE", cut into the shaft, meanwhile the air or gas is aspirated in the identical ratio by the passage, "FG".


Hans-Dieter Beckey

Hans-Dieter Beckey (8 June 1921 - 18 June 1992) was an German physicist and mass spectrometry researcher known for his work on field desorption.
Career and Research.
Beckey graduated from the University of Hamburg in 1950 and then received his PhD in the group of Wilhelm Groth at the University of Bonn in 1952. He wrote his habilitation in 1959 and became full professor of physical chemistry at the University of Bonn in 1966. In 1958, he used field ionization (FI) together with mass spectrometry to transfer ions into the gas phase. Using high field strengths, he was able to show that FI could ionize labile molecules that were not amenable to electron ionization (EI) due to the latters propensity to fragment ions. He thus established FI as a complementary technique to EI. He also showed that FI is suited to study the decomposition kinetics of organic molecules in the gas phase. However, his most important contribution to mass spectrometry was the invention of field desorption, a soft ionization technique suitable for large molecules including biopolymers. After his illness forced him to cease working, his co-worker Hans-Rolf Schulten continued this work.
Beckey received the Nernst Prize (now the Nernst–Haber–Bodenstein Prize) from the German Bunsen Society for Physical
Chemistry in 1964.
Beckey was married to Gudrun Kischke (in 1951) and they had three children. He was forced to resign in 1979 due to an illness that had acquired in 1969. He died in 1992.


Glen Cowan

Glen Cowan is a professor of Particle Physics at Royal Holloway, University of London. He has made a considerable contribution to the ATLAS experiment at the Large Hadron Collider.
Education.
Cowan obtained a Bachelor of Science in Physics in 1981 from UCLA. In 1988 he completed his PhD at UC Berkeley where he focused his researched on the TPC/Two-Gamma Experiment.
Career.
Cowan was a postdoctoral researcher between 1988 - 1992 at the Max Planck Institute for Physics in Munich and at the University of Siegen. At both institutes he worked on the ALEPH experiment and Large Electron–Positron Collider at CERN. He joined the Royal Holloway academic staff in 1998.
Cowan writes the statistics chapter of the Particle Data Group
Research.
Cowan is involved with analysing data and developing software for the ATLAS experiment at the LHC. He is also involved in searching for physics beyond the standard model, such as Supersymmetry.


Non-relativistic spacetime

In physics, a non-relativistic spacetime is any mathematical model that fuses "n"–dimensional space and "m"–dimensional time into a single continuum other than the (3+1) model used in relativity theory.
In the sense used in this article, a spacetime is deemed "non-relativistic" if (a) it deviates from (3+1) dimensionality, even if the postulates of special or general relativity are otherwise satisfied, or if (b) it does not obey the postulates of special or general relativity, regardless of the model's dimensionality.
Introduction.
There are many reasons why spacetimes may be studied that do not satisfy relativistic postulates and/or that deviate from the apparent (3+1) dimensionality of the known universe.
Galilean/Newtonian spacetime.
The classic example of a non-relativistic spacetime is the spacetime of Galileo and Newton. It is the spacetime of everyday "common sense". Galilean/Newtonian spacetime assumes that space is Euclidean (i.e. "flat"), and that time has a constant rate of passage that is independent of the state of motion of an observer, or indeed of anything external.
Newtonian mechanics takes place within the context of Galilean/Newtonian spacetime. For a huge problem set, the results of computations using Newtonian mechanics are only imperceptibly different from computations using a relativistic model. Since computations using Newtonian mechanics are considerably simpler than those using relativistic mechanics, as well as correspond to intuition, most everyday mechanics problems are solved using Newtonian mechanics.
Model systems.
Efforts since 1930 to develop a consistent quantum theory of gravity have not yet produced more than tentative results. The study of quantum gravity is difficult for multiple reasons. Technically, general relativity is a complex, nonlinear theory. Very few problems of significant interest admit of analytical solution, and numerical solutions in the strong-field realm can require immense amounts of supercomputer time.
Conceptual issues present an even greater difficulty, since general relativity states that gravity is a consequence of the geometry of spacetime. To produce a quantum theory of gravity would therefore require quantizing the basic units of measurement themselves: space and time. A completed theory of quantum gravity would undoubtedly present a visualization of the Universe unlike any that has hitherto been imagined.
One promising research approach is to explore the features of simplified models of quantum gravity that present fewer technical difficulties while retaining the fundamental conceptual features of the full-fledged model. In particular, general relativity in reduced dimensions (2+1) retains the same basic structure of the full (3+1) theory, but is technically far simpler. Multiple research groups have adopted this approach to studying quantum gravity.
"New physics" theories.
The idea that relativistic theory could be usefully extended with the introduction of extra dimensions originated with Nordstöm's 1914 modification of his previous 1912 and 1913 theories of gravitation. In this modification, he added an additional dimension resulting in a 5-dimensional vector theory. Kaluza–Klein theory (1921) was an attempt to unify relativity theory with electromagnetism. Although at first enthusiastically welcomed by physicists such as Einstein, Kaluza–Klein theory was too beset with inconsistencies to be a viable theory.
Various superstring theories have effective low-energy limits that correspond to classical spacetimes with alternate dimensionalities than the apparent dimensionality of the observed universe. It has been argued that all but the (3+1) dimensional world represent "dead worlds" with no observers. Therefore, on the basis of anthropic arguments, it would be "predicted" that the observed universe should be one of (3+1) spacetime.
Space and time may not be fundamental properties, but rather may represent emergent phenomena whose origins lie in quantum entanglement.
It had occasionally been wondered whether it is possible to derive sensible laws of physics in a universe with more than one time dimension. Early attempts at constructing spacetimes with extra timelike dimensions inevitably met with issues such as causality violation and so could be immediately rejected, but it is now known that viable frameworks exist of such spacetimes that can be correlated with general relativity and the Standard Model, and which make predictions of new phenomena that are within the range of experimental access.
Possible observational evidence.
Observed high values of the cosmological constant may imply kinematics significantly different from relativistic kinematics. A deviation from relativistic kinematics would have significant cosmological implications in regards to such puzzles as the "missing mass" problem.
To date, general relativity has satisfied all experimental tests. However, proposals that may lead to a quantum theory of gravity (such as string theory and loop quantum gravity) generically predict violations of the weak equivalence principle in the 10−13 to 10−18 range. Currently envisioned tests of the weak equivalence principle are approaching a degree of sensitivity such that "non-discovery" of a violation would be just as profound a result as discovery of a violation. Non-discovery of equivalence principle violation in this range would suggest that gravity is so fundamentally different from other forces as to require a major reevaluation of current attempts to unify gravity with the other forces of nature. A positive detection, on the other hand, would provide a major guidepost towards unification.
Condensed matter physics.
Research on condensed matter has spawned a two-way relationship between spacetime physics and condensed matter physics:


Evgeni Gross

Evgenii Fedorovich Gross (1897 – 1972) was a Soviet physicist working in optics and spectroscopy of condensed matter.
He graduated from Leningrad University in 1924. He became a correspondent member of the USSR Academy of Sciences in 1946.
His two key achievements are the experimental observation of the fine structure of Rayleigh scattering line due to Brillouin-Mandelstam light scattering on acoustic waves in condensed matter (1930) and the experimental discovery of the exciton (in semiconductor crystals of cuprous oxide) through evidence of its hydrogen-like optical spectrum.


Anna Maria Nobili

Anna Maria Nobili is an Italian physicist active in the field of gravitational physics.
Her institution is Pisa University. She authored a number of papers on satellite dynamics and co-authored a book with Andrea Milani and P. Farinella on the orbital perturbations induced by non-gravitational forces. After having published several papers on celestial mechanics, also in collaboration with Clifford Will and E. Myles Standish, Nobili is now Principal Investigator of the Galileo Galilei (GG) experiment aimed to improve the accuracy
of the equivalence principle lying at the foundation of general relativity and of other metric theories of gravity.
Bibliometric information.
As of November 2013, according to the NASA ADS database, the h-index of A.M. Nobili is 17, with a total number of citations (self-citations excluded) equal to about 1000. Her tori index and riq index are 19.2 and 118, respectively.


Iranian Journal of Physics Research

The Iranian Journal of Physics Research () is a quarterly peer-reviewed open access scientific journal of physics published by the Physics Society of Iran. It was established in 1995, with S. Mohammad Amini as editor-in-chief. Originally publishing exclusively in Persian, the journal began accepting articles in English as well in 1999. In 2004 the publication frequency was raised from 2 to 4 issues per year. The journal is abstracted and indexed in Scopus.


Valerie Gibson

Valerie Gibson , also known as Val Gibson, is a Professor of Physics and Head of the High Energy Physics group at the University of Cambridge.
Education.
Gibson completed a Bachelors in Physics at the University of Sheffield in 1983. She achieved a DPhil in experimental particle physics in 1986 from The Queen's College, Oxford.
Career.
In 1987 she became a fellow in the Experimental Physics Division at CERN. She joined the Cavendish Laboratory in 1989 on a five-year SERC Advanced Fellowship. In 1989 she also received a Stokes Senior Research Fellowship at Pembroke College. She was appointed as University Lecturer and Fellow of Trinity College in 1994. She was awarded a Royal Society Leverhulme Trust Fellowship in 2007. Gibson was appointed Professor in 2009.
She began work on the Muon Scattering Experiment at Paul Scherrer Institute. She has worked on the LHCb experiment since the first beam of particles were injected into the Large Hadron Collider in 2008. Gibson has overall responsibility for data acquisition from the ring imaging Cherenkov detectors. Gibson was the UK spokesperson for the LHCb experiment between 2004 and 2008. Today she is chair of the CERN Collaboration Board and lead of the University of Cambridge's LHCb team. Gibson was part of the discovery of CP violation in the Kaon system.
Public engagement.
Gibson is a keen science communicator, interested in taking science to a wider range of audiences. She regularly discusses particle physics discoveries in the media. She developed the card game "Hunt the Higgs" and has acted as an adviser for exhibitions at the Science Museum. She is a patron of the Gravity Fields Festival. Alongside her research group, Gibson exhibited at the Royal Society Summer Science Exhibition.
Gibson has spent her career championing women in science. She believes it is her duty "to encourage younger women in their careers and say ‘it is possible’". She has been part of the University of Cambridge's Athena SWAN and Project Juno committees. In 2014, the University of Cambridge were awarded the first gold Athena SWAN award. She won the WISE Campaign Leader Award in 2013. She is chair of the Institute of Physics Juno panel. In 2016 she launched a three-day residential program for young women interested in physics at the Cavendish Laboratory. In 2016 she won a Royal Society Athena Prize for increasing gender diversity in mathematics, having been nominated by the Institute of Physics. She was a keynote speaker at the 2018 Conference for Undergraduate Women in Physics.
Gibson was appointed Officer of the Order of the British Empire (OBE) in the 2021 New Year Honours for services to science, women in science and public engagement.


Tritium Systems Test Assembly

The Tritium Systems Test Assembly (TSTA) was a facility at Los Alamos National Laboratory dedicated to the development and demonstration of technologies required for fusion-relevant deuterium-tritium processing. Facility design was launched in 1977. It was commissioned in 1982, and the first tritium was processed in 1984. The maximum tritium inventory was 140 grams.


Theodore H. Berlin

Theodore H. Berlin (8 May 1917, New York City – 16 November 1962, Baltimore) was an American theoretical physicist.
Berlin graduated in 1939 with B.S. in chemical engineering from Cooper Union. He graduated in 1940 with M.S. and in 1944 with Ph.D. from the University of Michigan. His thesis advisor was Kasimir Fajans.
He was a research physicist from 1944 to 1946 at the University of Michigan, a lecturer from 1946 to 1947 at Johns Hopkins University, and an associate professor from 1948 to 1949 at Northwestern University. At Johns Hopkins University he was from 1949 to 1954 an associate professor and from 1955 to 1961 a full professor. As a Guggenheim Fellow for the academic year 1952–1953, he was at the Institute for Advanced Study on leave of absence from Johns Hopkins. From 1961 until his death from a heart attack in 1962 he was a full professor at The Rockefeller University.
Berlin was a Fellow of the American Physical Society. He was an associate editor for the "Journal of Chemical Physics", "Physical Review", and "Physical Review Letters". He was appointed to the editorial board of "The Physics of Fluids", starting on 1 January 1962. His doctoral students include Louis Witten.
At the beginning of his career, Berlin did research on physical chemistry (quantum theory of molecules). He is known for his work with Kac on the "spherical model", a generalization of the Ising model of statistical mechanics, which was developed as a mathematical model for ferromagnetism. In contrast to the Ising model, the spherical model's spin variable on the lattice can assume continuous values (with the restriction that the sum of the squares of the spins is equal to the number of lattice positions). The spherical model can be solved exactly in the presence of an external field and shares that property of exact solvability with very few models of ferromagnetism.
In 1944 Berlin married Patricia May Cleary. Upon his death he was survived by his widow and their sons, Geoffrey N., Dennis A., Michael K., and Alexander L. A daughter died in infancy.


Halo nucleus

In nuclear physics, an atomic nucleus is called a halo nucleus or is said to have a nuclear halo when it has a core nucleus surrounded by a "halo" of orbiting protons or neutrons, which makes the radius of the nucleus appreciably larger than that predicted by the liquid drop model. Halo nuclei form at the extreme edges of the table of nuclides — the neutron drip line and proton drip line — and have short half-lives, measured in milliseconds. These nuclei are studied shortly after their formation in an ion beam.
Typically, an atomic nucleus is a tightly bound group of protons and neutrons. However, in some nuclides, there is an overabundance of one species of nucleon. In some of these cases, a nuclear core and a halo will form.
Often, this property may be detected in scattering experiments, which show the nucleus to be much larger than the otherwise expected value. Normally, the cross-section (corresponding to the classical radius) of the nucleus is proportional to the cube root of its mass, as would be the case for a sphere of constant density. Specifically, for a nucleus of mass number "A", the radius "r" is (approximately)
where formula_2 is 1.2 fm.
One example of a halo nucleus is 11Li, which has a half-life of 8.6 ms. It contains a core of 3 protons and 6 neutrons, and a halo of two independent and loosely bound neutrons. It decays into 11Be by the emission of an antineutrino and an electron. Its mass radius of 3.16 fm is close to that of 32S or, even more impressively, of 208Pb, both much heavier nuclei.
Experimental confirmation of nuclear halos is recent and ongoing. Additional candidates are suspected. Several nuclides including 9B, 13N, and 15N are calculated to have a halo in the excited state but not in the ground state.
List of known nuclides with nuclear halo.
Nuclei that have a neutron halo include 11Be and 19C. A two-neutron halo is exhibited by 6He, 11Li, 17B, 19B and 22C.
Two-neutron halo nuclei break into three fragments and are called Borromean because of this behavior, analogously to how all three of the Borromean rings are linked together but no two share a link. For example, the two-neutron halo nucleus 6He (which can be taken as a three-body system consisting of an alpha particle and two neutrons) is bound, but neither 5He nor the dineutron is. 8He and 14Be both exhibit a four-neutron halo.
Nuclei that have a proton halo include 8B and 26P. A two-proton halo is exhibited by 17Ne and 27S. Proton halos are expected to be rarer and more unstable than neutron halos because of the repulsive forces of the excess proton(s).


Tamara Davis

Tamara Maree Davis is an Australian astrophysicist. , she is a professor in the School of Mathematics and Physics at the University of Queensland, where she has been employed since 2008.
She was awarded an Australian Laureate Fellowship in 2018, and the Australian Academy of Science awarded her their Nancy Millis Medal in 2015. She was Australian Institute of Physics Women in Science Lecturer in 2011. She received the Astronomical Society of Australia's Louise Webster Prize in 2009.
As an athlete, Davis has competed for Australia at an international level in Ultimate Frisbee.
Education.
Davis completed her Ph.D in astrophysics at the University of New South Wales in 2004. She also has a BSc in physics and a BA in philosophy.


Eduard Riecke

Eduard Riecke (1 December 1845 – 11 June 1915) was a German experimental physicist.
Riecke studied physics at the Polytechnic in Stuttgart, at the University of Tübingen and at the University of Göttingen under Wilhelm Weber and Friedrich Kohlrausch, where he received his doctorate in 1871 and qualified as a professor shortly thereafter. In 1873 he became associate professor and in 1881 full professor, which he remained until his death.
He conducted experiments on electrical conduction in metals for which he further developed a model of management by electrons began by Paul Drude. With the model, among other things, the decrease in conductivity could be explained with increase in temperature. Later he worked among others with electricity conduction in gases.
The Bavarian Academy of Sciences appointed him in 1909 as a corresponding member. His students include Johannes Stark.
External links.
[[Category:1845 births]]
[[Category:1915 deaths]]
[[Category:German physicists]]


Labradorescence


Hope Ishii

Hope A. Ishii is an American scientist and the Director of the Advanced Electron Microscopy Center at the Hawai'i Institute of Geophysics and Planetology (HIGP) at the University of Hawai'i. Her work focuses on analysis and characterization of small solar system objects such as comet and asteroid dust, primarily by means of electron microscopy and x-ray spectroscopy, sometime from samples collected in space using aerogel.
She is a research faculty member at the University of Hawaiʻi at Mānoa, and an affiliate researcher at Lawrence Berkeley National Laboratory.
Education.
Ishii received her Ph.D from Stanford University in 2002, working on the characterization of amorphous Molybdenum-Germanium alloy by anomalous x-ray scattering; her MS in Physics and Engineering from Chalmers University of Technology, 1995 and her BS in Material Science and Engineering from Cornell University in 1994.


Neville Robinson

Frank "Neville" Hosband Robinson (13 April 1925, West Bromwich, Staffordshire, England – 19 October 1996, Colmar, France) was an English physicist.
Neville Robinson was educated at The Leys School in Cambridge, England, and Christ's College, Cambridge, where he read Physics.
Robinson initially worked as a civil servant at the Services Electronic Research Laboratory (SERL) in Baldock, Hertfordshire, under the director Robert Sutton. He then moved to the Clarendon Laboratory at Oxford University to undertake a DPhil doctorate degree in low temperature physics, as a Nuffield Research Fellow (1950–54). With Jim Daniels and Michael Grace, he produced an example of nuclear orientation for the first time. Then in 1951, in the first nuclear cooling experiment, he produced the lowest temperature ever achieved until then at only ten millionths of a degree Kelvin above absolute zero.
Robinson was an English Electric Research Fellow from 1955–59. He was a Faculty Fellow at Nuffield College, Oxford from 1958 to 1961, immediately followed by becoming a founding Fellow of St Catherine's College, Oxford where he stayed until his retirement in 1992. He was also a Senior Research Officer at Oxford University during 1959 to 1992, working at the Clarendon Laboratory. During his career, he visited Bell Telephone Laboratories in New Jersey, United States, three times while on sabbatical leave (during 1954–55, 1965–66, and 1973–74).
In 1973, Robinson published the book "Macroscopic Electromagnetism", a standard text. His paper "Microwave shot noise and minimum noise factor" was awarded the Clerk Maxwell Prize in 1954 by the British Institution of Radio Engineers. Importantly, he invented the Robinson oscillator in the field of Nuclear Magnetic Resonance (NMR), which now forms the underlying basis of Magnetic Resonance Imaging (MRI) systems used in many hospitals.
Family.
Robinson married Daphne Coulthard in 1952. They had one son, the author Andrew Robinson and two daughters. He died of a heart attack, aged 71, in Colmar, France.


Liouville gravity


Giovanni di Casali

Giovanni (or Johannes) di Casali (or da Casale; c. 1320 – after 1374) was a friar in the Franciscan Order, a natural philosopher and a theologian, author of works on theology and science, and a papal legate.
He was born in Casale Monferrato around 1320 and entered the Franciscan order in the Genoese province. He was lecturer in the Franciscan stadium at Assisi from 1335 to 1340. He subsequently was lector at Cambridge ca. 1340 to 1341, where he encountered the mathematical physics developed by the Oxford Calculators. He was also an inquisitor in Florence, and a lector in Bologna from 1346 to ca. 1352. In 1375 Pope Gregory XI appointed him papal legate to the court of King Frederick of Sicily.
About 1346 he wrote a treatise "De velocitate motus alterationis" (On the Velocity of the Motion of Alteration) which was subsequently printed in Venice in 1505. In it he presented a graphical analysis of the motion of accelerated bodies. His teachings in mathematical physics influenced scholars at the University of Padua and, it is believed, may have ultimately influenced the similar ideas presented over two centuries later by Galileo Galilei.


Francis Everitt

C. W. Francis Everitt (born 8 March 1934) is a US-based English physicist working on experimental testing of general relativity.
Everitt was educated at Imperial College London and the University of Pennsylvania in low-temperature physics. He is Professor at the Hansen Experimental Physics Laboratory of Stanford University and is also an Associate Member of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).
Everitt is Principal Investigator of the Gravity Probe B mission mainly aimed to test frame-dragging at an expected accuracy of 1%. According to general relativity, it is an effect induced by the rotation of the Earth on orbiting gyroscopes. Everitt spent more than 40 years on the project and was awarded with the NASA Distinguished Public Service Medal. The results were published in Physical Review Letters in May 2011. The results confirm general relativity's predictions, though not to the project's ambitious goal of 1% precision.
In 1985, along with Remo Ruffini, Riccardo Giacconi, Abdus Salam, Paul Boynton, George Coyne, and Fang Li-Zhi, Professor Everitt co-founded the International Center for Relativistic Astrophysics. Everitt is the current Chairman of the ICRANet Steering Committee for the ICRANet Center at the Leland Stanford Junior University.
Bibliometric information.
As of November 2013, according to the NASA ADS database, the h-index of C.W.F. Everitt is 18, with a total number of citations (self-citations excluded) of about 900. The tori index and the riq index are 12.1 and 62, respectively.


Axel Wenner-Gren

Axel Lennart Wenner-Gren (5 June 1881 – 24 November 1961) was a Swedish entrepreneur and one of the wealthiest men in the world during the 1930s.
Early life.
He was born on 5 June 1881 in Uddevalla, a town on the west coast of Sweden. He was the fourth of six children (four girls and two boys) born to Leonard and the much younger Alice Wenner-Gren (née Albin), though only three of them grew to adulthood, Axel himself, his oldest sister Anna, and his younger brother Hugo.
Having spent his school years in Uddevalla, Wenner-Green moved to Gothenburg where he was employed for five years in the spice importing company of a maternal uncle. During this time, he learned English, French, and German at the local Berlitz school, and music at the local YMCA
In 1902, at the age of 21, he left Sweden to further his studies in Germany. He first studied in the university town of Greifswald where he took some summer courses before moving on to Berlin where he studied at the Berliner Handelsakademie from which he graduated much sooner than usual.
Career.
After some difficulty, he found work with the German subsidiary of Alfa Laval Separator where he developed skills as a salesman, before quitting in 1904 to work selling agricultural machinery near Stuttgart which, with financial support from his father, had become his first financial enterprise.
In 1908, he traveled to America where he learned about engines for agricultural use, returning to Europe the same year. While in Vienna in 1908 he saw the Santo vacuum cleaner in the shop of Gustaf Paalen who had exclusive rights to distribute them throughout Europe. After initially failing to become a European distributor for the Santo vacuum cleaner in his own right, he entered into a partnership with Paalen, purchasing a twenty percent interest in the company.
Earlier in his life he notably collaborated with Fredrik Ljungström.
Wenner-Gren amassed a fortune from his early insight that the industrial vacuum cleaner could be adapted for domestic use. Soon after the First World War he persuaded the Swedish lighting company (called Lux at the time, but with his suggestion to rename it to Electrolux) for which he then worked (securing the contract to floodlight the opening ceremony of the Panama Canal, among other successes), to buy the patent to a home vacuum cleaner. He asked that instead of compensating him in cash, he would receive company stock based on the sales of the vacuum cleaner. The Electrolux cleaner was so successful that by the early 1930s, Wenner-Gren had become the majority owner of Electrolux, and the firm was a leading brand in both vacuum cleaner and refrigerator technology.
Wenner-Gren also diversified his interests into the ownership of newspapers, banks and arms manufacturers, and acquired many of the holdings of the disgraced safety-match tycoon Ivar Kreuger. In Mexico in the 1930s, he was in economic alliance with Maximino Ávila Camacho, strongman of the Mexican state of Puebla, whose brother Manuel Ávila Camacho became President of Mexico in 1940.
World War II blacklisting.
Wenner-Gren was reported to be a friend of Hermann Göring, whose first wife was a Swede, and in the late 1930s convinced himself that he could avert the coming world war by acting as a conduit between Göring and the British and American governments. His efforts proved unsuccessful, with all parties regarding him as a self-promoting nuisance without much influence on the plans of the Nazi regime. However, others are suspicious of his role in the war, citing how (his) original Bank of the Bahamas was used to fund the Nazis and his friendship with Göring as potential proof of his private support for the Nazis.
A disconsolate Wenner-Gren retired to his estate in The Bahamas, in Hog Island (now Paradise Island), where he resumed his friendship with the islands' governor, the Duke of Windsor and former King of the United Kingdom Edward VIII. Early in the war his rumored friendship with Göring and the suspected German sympathies of the Duke led first the Americans and, following their lead, the British, to place him on an economic blacklist, enabling them to freeze his assets in Nassau. There proved to be little or no foundation to their suspicions that Wenner-Gren was a Nazi agent, notwithstanding the appearance of his steam yacht "Southern Cross" (the world's largest at the time) along with ships from the Allied Navies at the site of the sinking of the liner on the first day of the war. Wenner-Gren's yacht "Southern Cross" rescued over three hundred survivors of the sinking and transferred some to nearby Allied ships and others continued to the U.S.
Other ventures.
In the 1950s, Axel Wenner-Gren also got involved in the early computer business. For a railroad project connecting California with Alaska, he got in touch with Glenn Hagen, previously an engineer with Northrop Aircraft, who had founded Logistics Research in Redondo Beach outside Los Angeles, developing computers based on magnetic drum memory. In November 1952, Wenner-Gren helped the company to incorporate. He soon controlled the company and renamed it ALWAC (the Axel L. Wenner-Gren Automatic Computer). ALWAC I was used in 1953, ALWAC II and ALWAC III in 1954, ALWAC III-E in 1955. In 1956 and 1957, the model ALWAC III-E was considered a competitor to the IBM 650, having fewer parts and good economy, but no more than 30 units seem to have been delivered. Soon after this, magnetic drum machines were made obsolete by the introduction of the magnetic core memory. By 1956 the number of employees tripled to over 300 and the company was relocated to an industrial park in Hawthorne, California. The appearance of the transistor in the electronics industry in 1957 was a financial shock for all vacuum tube computer makers and by 1958 ALWAC in Hawthorne closed and its employees, with the help of Wenner-Gren himself, were successfully hired by Litton Industries and Autonetics and several smaller electronics companies. The follow-up ALWAC 800 was a failed design that never went beyond prototype, using not only core memory but also magnetic logic (a combination of semiconductor diodes and magnetic cores, cf. Hewitt Crane), and presold contracts nearly ruined the company. Development was transferred to Sweden in 1958. The next model, named Wegematic 1000, a slight upgrade of the III-E, was shipped in 1960. Only a dozen were delivered and half of them were give-aways to universities, including one unit for the Weizmann Institute in Israel. In exchange, Wenner-Gren received several honorary titles.
Among Wenner-Gren's other interests were monorail train systems. His company, ALWEG, built the original Disneyland Monorail System in 1959 and the Seattle Center Monorail in 1962. Wenner-Gren continued his fascination with speculative railway projects, as he collaborated with Canadian W.A.C. Bennett to build a railway north from Prince George into the untapped Peace River, Rocky Mountain Trench and eventually Alaska. Parts of the railway were built by the Pacific Great Eastern Railway after Wenner-Gren's death, including the needless Fort Nelson branch, yet the meeting produced outcomes lasting to this day. The interest in the north spurred a spate of mega-industrial projects in the region: the Bennett Dam flooding vast valleys, gas pipelines and plants at Taylor, coal mines and pulp mills.
Personal life.
In late 1909, while returning from a trip to America on board a trans-Atlantic liner, he met Marguerite Gauntier Liggett who had been born on 15 October 1891 in Kansas City, Missouri. She was traveling with her sister, actress Gene Gauntier, to Europe to complete her musical training as an opera singer. After a brief romance at sea, they traveled to London, where they married on 14 December 1909 before traveling on to Berlin where she would complete her studies.
The Viking Fund.
Wenner-Gren also founded and endowed The Viking Fund in 1941, an organization supporting anthropological research. In 1941, the endowment funded the Wenner-Gren Aeronautical Research Laboratory, now called the Wenner-Gren Laboratory at the University of Kentucky. The lab has since changed its focus to Biomedical Engineering. The Viking fund was later renamed the Wenner-Gren Foundation for Anthropological Research.
References.
Literature.
(On pp. 21–22, points to Leifland 1989 as conclusive evidence that Wenner-Gren's blacklisting was a miscarriage of justice).


Slava Turyshev

Slava G. Turyshev () is a Russian physicist now working in the US at the NASA Jet Propulsion Laboratory (JPL). He is known for his investigations of the Pioneer anomaly, affecting Pioneer 10 and Pioneer 11 spacecraft, and for his attempt to recover early data of the Pioneer spacecraft to shed light on such a phenomenon. He is interested in:
He was the principal investigator of the LATOR mission aimed at testing parameterized post-Newtonian formalism with high accuracy. Dr. Turyshev chaired several workshops at the International Space Science Institute on the Pioneer anomaly and the flyby anomaly.
Bibliometric information.
As of November 2013, the h index of Turyshev, as released by the NASA ADS database, is 23, with more than 2000 non-self citations.
His tori index and riq index are 25.8 and 267, respectively.


Padre Bancalari

Padre Bancalari ("fl." 19th century) was professor of natural philosophy at the University of Genoa. In 1847, he discovered that flames were diamagnetic by showing that there were repulsed by a strong magnetic field.
References.
<br>


Noncommutative standard model

In theoretical particle physics, the non-commutative Standard Model (best known as Spectral Standard Model
<ref name="10.1007/JHEP09(2012)104">
</ref>
<ref name="10.1007/JHEP11(2013)132">
</ref>
), is a model based on noncommutative geometry that unifies a modified form of general relativity with the Standard Model (extended with right-handed neutrinos).
The model postulates that space-time is the product of a 4-dimensional compact spin manifold formula_1 by a finite space formula_2. The full Lagrangian (in Euclidean signature) of the Standard model minimally coupled to gravity is obtained as pure gravity over that product space. It is therefore close in spirit to Kaluza–Klein theory but without the problem of massive tower of states.
The parameters of the model live at unification scale and physical predictions are obtained by running the parameters down through Renormalization.
It is worth stressing that it is more than a simple reformation of the Standard Model. For example, the scalar sector and the fermions representations are more constrained than in Effective field theory.
Motivation.
Following ideas from Kaluza–Klein and Albert Einstein, the spectral approach seeks unification by expressing all forces as pure gravity on a space formula_3.
The group of invariance of such a space should combine the group of invariance of general relativity formula_4 with formula_5, the group of maps from formula_1 to the standard model gauge group formula_7.
formula_4 acts on formula_9 by permutations and the full group of symmetries of formula_3 is the semi-direct product:
formula_11
Note that the group of invariance of formula_3 is not a simple group as it always contains the normal subgroup formula_9. It was proved by Mather
<ref name="10.1090/S0002-9904-1974-13456-7">
</ref>
and Thurston
<ref name="10.1090/S0002-9904-1974-13475-0">
</ref>
that for ordinary (commutative) manifolds, the connected component of the identity in formula_4 is always a simple group, therefore no ordinary manifold can have this semi-direct product structure.
It is nevertheless possible to find such a space by enlarging the notion of space.
In noncommutative geometry, spaces are specified in algebraic terms. The algebraic object corresponding to a diffeomorphism is the automorphism of the algebra of coordinates. If the algebra is taken non-commutative it has trivial automorphisms (so-called inner automorphisms). These inner automorphisms form a normal subgroup of the group of automorphisms and provide the correct group structure.
Picking different algebras then give rise to different symmetries. The Spectral Standard Model takes as input the algebra formula_15 where formula_16 is the algebra of differentiable functions encoding the 4-dimensional manifold and formula_17 is a finite dimensional algebra encoding the symmetries of the standard model.
History.
First ideas to use noncommutative geometry to particle physics appeared in 1988-89
,<ref name="10.1016/0370-2693(89)90083-X">
</ref><ref name="10.1063/1.528917">
</ref> and were formalized a couple of years later by Alain Connes and John Lott in what is known as the Connes-Lott model
.<ref name="10.1016/0920-5632(91)90120-4">
</ref> The Connes-Lott model did not incorporate the gravitational field.
In 1997, Ali Chamseddine and Alain Connes published a new action principle, the Spectral Action
,<ref name="10.1007/s002200050126">
</ref> that made possible to incorporate the gravitational field into the model. Nevertheless, it was quickly noted that the model suffered from the notorious fermion-doubling problem (quadrupling of the fermions)
<ref name="10.1103/PhysRevD.55.6357">
</ref>
<ref name="10.1016/S0370-2693(97)01310-5">
</ref> and required neutrinos to be massless. One year later, experiments in Super-Kamiokande and Sudbury Neutrino Observatory began to show that solar and atmospheric neutrinos change flavors and therefore are massive, ruling out the Spectral Standard Model.
Only in 2006 a solution to the latter problem was proposed, independently by John W. Barrett<ref name="10.1063/1.2408400">
</ref> and Alain Connes,<ref name="10.1088/1126-6708/2006/11/081">
</ref> almost at the same time. They show that massive neutrinos can be incorporated into the model by disentangling the KO-dimension (which is defined modulo 8) from the metric dimension (which is zero) for the finite space. By setting the KO-dimension to be 6, not only massive neutrinos were possible, but the see-saw mechanism was imposed by the formalism and the fermion doubling problem was also addressed.
The new version of the model was studied in
<ref name="10.4310/ATMP.2007.v11.n6.a3">
</ref> and under an additional assumption, known as the "big desert" hypothesis, computations were carried out to predict the Higgs boson mass around 170 GeV and postdict the Top quark mass.
In August 2008, Tevatron experiments excluded a Higgs mass of 158 to 175 GeV at the 95% confidence level. Alain Connes acknowledged on a blog about non-commutative geometry that the prediction about the Higgs mass was invalidated. In July 2012, CERN announced the discovery of the Higgs boson with a mass around 125 GeV/"c"2.
A proposal to address the problem of the Higgs mass was published by Ali Chamseddine and Alain Connes in 2012
 by taking into account a real scalar field that was already present in the model but was neglected in previous analysis.
Another solution to the Higgs mass problem was put forward by Christopher Estrada and Matilde Marcolli by studying renormalization group flow in presence of gravitational correction terms.<ref name="10.1142/S0219887813500369">
</ref>


Electric field NMR

Electric field NMR (EFNMR) spectroscopy is the NMR spectroscopy where additional information on a sample being probed is obtained from the effect of a strong, externally applied, electric field on the NMR signal.


Documation

Documation was an American Stock Exchange-listed computer hardware manufacturer founded in 1969 in Melbourne, Florida that went public in 1976. They made (punched card) card readers
used in some American elections 3 decades later. They also produced Impact Line printers.
In late 1980, Storage Technology Corporation (STC) acquired Documation, which was subsequently spun off, and those companies which subdivided from it, most of which use Documation-like names, no longer manufacture computer peripherals.
Documation was described as "a financially troubled printer manufacturer."
IMPACT Line printers.
Documation's "IMPACT 3000", named for its 3,000 lines per minute rating, was followed a year later by the 3,800 LPM "IMPACT 3800".
A 5,000 lines per minute printer was introduced in 1986, by which time the company was operating under the name StorageTek Printer Corp. Like earlier impact printer models, it is manufactured in Florida. At the time of the Series 5000's introduction, the company said that "impact printers dominate 85 percent of the market."
The company's laser printers are rebadged from Siemens.
Documation's Burroughs-rebadged printers.
Four Documation printers, rebadged by Burroughs as DOC 2000B, DOC 1800B, DOC 1500B and DOC 1250B were introduced in 1978.
Per their names, they were rated at "2,000-, 1,800-, 1,500- and 1,250" lines per minute, when using 48 character ASCII.
Card readers.
Among the card readers made by Documation for minicomputers in the 1970s were:
Their card readers have been used in elections, including the 2000 "Chads" election in Florida.
End-user market.
In late 1977 Documation successfully entered the end-user market. They initially focused on selling card readers to end-users; their model 6501 is IBM-compatible.
They subsequently added line printers to the equipment they sold to end-users.
Storage Technology Corporation and thereafter.
By 1992, the name Documation was no longer affiliated with Storage Technology Corporation in the US, but the latter still owned two Documation-named subsidiaries, one in France and the other in UK.
Ubeo, DOCUmation, Documation Inc.
The New York Times (adding "Inc") continued earnings and other coverage in the 1980s and early 1990s.
Ubeo Business Services and DOCUmation are regional companies somewhat related to the original Documation that had been acquired by StorageTek.
"Documation Inc" is covered by Bloomberg;
DOCUmation is a name that came into being in 1997, post-Storage Tek. At that point, neither company manufactured card readers or printers. Their niche is service and distribution of printers and duplicators/copying machines.
Another "Documation" is named "Documation, LLC" (founded 1994) and is based in Wisconsin. Their focus is described by Bloomberg as "print and digital media solutions ... direct mail marketing ... and graphic design."
Ubeo was a breakaway from DOCUmation, which was formed in the late 1990s by a merger of two San Antonio, Texas companies.
Before their May 2017 split they were known as DOCUmation of San Antonio
Ubeo was acquired by Sentinel Capital Partners in 2018.
DOCUmation acquired DocumentWorx November 2018 and renamed it DocumentWORKS.


D. P. Woodruff

David Phillip Woodruff FRS is a British physicist, professor at University of Warwick, and member of the Surface, Interface & Thin Films group.
Woorduff is a fellow of the Institute of Physics, and the Woodruff Thesis prize is named in his honour. He won the Nevill Mott Medal and Prize in 2003, and Max Born Medal and Prize in 2011.
Education.
He earned a B.Sc. from University of Bristol in 1965, and a Ph.D.(1968), and D.Sc. (1983) from Warwick University.
He formally retired in 2011 but remains research active as an emeritus professor.


Dieter Zeppenfeld

Dieter Zeppenfeld from the University of Wisconsin, was awarded the status of Fellow in the American Physical Society, after they were nominated by their Division of Particles and Fields in 1999, for pioneering contributions to the theoretical formulation of effective electroweak gauge boson interactions in a model-independent way and in the linear-sigma model, which initiated phenomenological and experimental studies of gauge boson anomalous coup.


Cecilia Jarlskog

Cecilia Jarlskog (born in 1941) is a Swedish theoretical physicist, working mainly on elementary particle physics.
Jarlskog obtained her doctorate in 1970 in theoretical particle physics at the Technical University of Lund. She is known for her work on CP violation in the electroweak sector of the Standard Model, introducing what is known as the Jarlskog invariant, and for her work on grand unified theories (see Georgi–Jarlskog mass relation).
Research interests.
Cecilia Jarlskog is mainly known for her study and expertise in theoretical particle physics. Her studies include research on the ways that sub-atomic and electronic constituents of matter cohere or lose their symmetry, matter and antimatter asymmetry, mathematical physics, neutrino physics, and grand unification.
The Jarlskog invariant or rephasing-invariant CP violation parameter, is an invariant quantity in particle physics, which is in the order of ±2.8 x 10−5. This parameter is related to the unitarity conditions of the Cabibbo–Kobayashi–Maskawa matrix, which can be expressed as triangles whose sides are products of different elements of the matrix. As such, the Jarlskog invariant can be written as J = ±Im(VusVcbVV), which amounts to twice the area of the unitarity triangle. Because the area vanishes for the specific parameters in the Standard Model for which there would be no CP violation, this invariant is thus very useful to quantify the non-conservation of the CP-symmetry in elementary particle physics. It is one of Jarlskog's foremost contributions to physics, the other being the many years that she was an active member of CERN.
She recalls her appreciation of CERN’s (European Organization for Nuclear Research) international atmosphere. Being a part of this community gave her great opportunities to meet and talk with inspiring physicists from across the world. She noted that she felt fortunate to have 'lived in a period when the amount of information revealed about the nature of the elementary constituents of matter and their interactions has been mind-boggling'.
At CERN, the European Organization for Nuclear Research, physicists and engineers probe the fundamental structure of the universe. The world's largest and most complex scientific instruments are employed to study the basic constituents of matter – fundamental particles. The particles are caused to collide at close to the speed of light, which affords physicists clues about the interactions of particles, and insights into the fundamental laws of nature.
Career.
Jarlskog was appointed professor at the University of Bergen, Norway, in 1976. In 1985 she switched to the University of Stockholm, Sweden, staying there until 1994. Since then, Jarlskog has been a professor at Lund University, her alma mater, where she had graduated in 1970 with a PhD in theoretical particle physics.
Jarlskog worked as a member of CERN from 1970 to 1972. In addition, she served on the CERN Scientific Policy committee from 1982 to 1988. In her remaining 6 years at CERN, she served as the Advisor to the Director General of CERN on Member States, from 1998 to 2004. Jarlskog was recognized by the Swedish Academy of Science community and was appointed as one of the 5 members of the Swedish Nobel Committee for Physics from 1989 to 2000, serving as chairman of that committee in 1999, when the prize was awarded to Gerard 't Hooft and Martinus J. G. Veltman.
Jarlskog is an Honorary Professor at three universities in China and received an honorary degree from the University College Dublin.
She was also Member of the Swedish Academy of Sciences (1984), Member of the Norwegian Academy of Sciences (1987), Member of the Board of Trustees of the Nobel Foundation (1996) and Member of the Academia Europaea (2005).
Books and articles.
Cecilia Jarlskog wrote the book, Portrait of Gunnar Källén: A Physics Shooting Star and Poet of Early Quantum Field Theory, while a member of CERN. Here she relates the accomplishments of a comparatively unknown physicist in quantum physics. Jarlskog has written many articles in her lifetime, among them are "Invariations of Lepton Mass Matrices and CP and T violation in Neutrino Oscillations", "On the Wings of Physics" and "Ambiguities Pertaining to Quark-Lepton Complementarity."


Frederick Guthrie

Prof Frederick Guthrie FRS FRSE (15 October 1833 – 21 October 1886) was a British physicist and chemist and academic author.
He was the son of Alexander Guthrie, a London tradesman, and the younger brother of mathematician Francis Guthrie. Along with William Fletcher Barrett he founded the Physical Society of London (now the Institute of Physics) in 1874 and was president of the society from 1884 till 1886. He believed that science should be based on experimentation rather than discussion.
Academic career.
His academic career started at University College, London, where he studied for three years. He studied chemistry under Thomas Graham and Alexander William Williamson and mathematics under Augustus De Morgan. In 1852, he submitted his brother Francis's observations to De Morgan.
In 1854 Guthrie went to Heidelberg to study under Robert Bunsen and then in 1855 obtained a Ph.D. at the University of Marburg under Adolph Wilhelm Hermann Kolbe.
In 1856 he joined Edward Frankland, professor of chemistry at Owens College, Manchester. In 1859 he went to the University of Edinburgh.
Guthrie synthetized mustard gas in 1860 from ethylene and sulfur dichloride. Gutherie probably was not the first to synthetize mustard gas, but he was among the first to document its toxic effects. Gutherie did his mustard gas synthesis almost simultaneously as Albert Niemann, who also synthetized mustard gas and noted its toxic effects in his own experiments. Both Gutherie and Niemann published their findings in 1 January 1860.
In 1860 Guthrie was elected a Fellow of the Royal Society of Edinburgh, his proposer being Lyon Playfair. He was elected a Fellow of the Royal Society of London in 1871.
He served as professor of chemistry and physics at the Royal College of Mauritius between 1861 and 1867.
Guthrie was later a professor at the Royal School of Mines in London, where he mentored the future experimental physicist C. V. Boys. He also mentored John Ambrose Fleming and was instrumental in turning his interest from chemistry to electricity.
He invented the thermionic diode 1873 (this was later given alternate credit to Edison's assistant W. J. Hammer).
Guthrie wrote the "Elements of Heat" in 1868 and "Magnetism and Electricity" in 1873 (published in 1876).
Guthrie was also a linguist, playwright, and poet. Under the name Frederick Cerny, he wrote the poems "The Jew" (1863) and "Logrono" (1877).
Guthrie died in 1886 and is buried in Kensal Green Cemetery in London.
Family.
He was married four times.
His son Frederick Bickell Guthrie was an agricultural chemist.


Neutron depth profiling

Neutron depth profiling (NDP) is a near-surface analysis technique that is commonly used to obtain profiles of concentration as a function of depth for certain technologically important light elements in nearly any substrate. The technique was first proposed by Ziegler "et al." to determine the concentration profiles of boron impurities in silicon substrates, and later improved by Biersack and coworkers to much of its existing capabilities.
Neutron depth.
In NDP, a thermal or cold neutron beam passes through a material and interacts with isotopes that emit monoenergetic charged particles upon neutron absorption; either a proton or an alpha, and a recoil nucleus. Since the charged particles are equally likely to be emitted in any direction, reaction kinematics are straightforward. Because low-energy neutrons are used, there is no significant momentum transfer from the neutron beam to the substrate, and the analysis is practically non-destructive. As charged particles move towards the surface, they are rapidly slowed down, primarily by interacting with the electrons of the substrate. The amount of energy loss is directly related to the thickness penetrated by the particle. The depth of the reaction site can be found by stopping power correlations.
Profiling.
Conventionally, the residual energies of charged particles and recoil nuclei have been measured by a silicon charged-particle detector; most commonly either a surface barrier detector (SBD) or a passivated implanted planar silicon (PIPS) detector. In this configuration, the semiconductor detector is placed opposite to the surface of the sample being analyzed, and an energy spectrum of charged particles emitted by the neutron-induced reaction is acquired.


Grand canonical ensemble

In statistical mechanics, a grand canonical ensemble (also known as the macrocanonical ensemble) is the statistical ensemble that is used to represent the possible states of a mechanical system of particles that are in thermodynamic equilibrium (thermal and chemical) with a reservoir. The system is said to be open in the sense that the system can exchange energy and particles with a reservoir, so that various possible states of the system can differ in both their total energy and total number of particles. The system's volume, shape, and other external coordinates are kept the same in all possible states of the system.
The thermodynamic variables of the grand canonical ensemble are chemical potential (symbol: ) and absolute temperature (symbol: ). The ensemble is also dependent on mechanical variables such as volume (symbol: ) which influence the nature of the system's internal states. This ensemble is therefore sometimes called the ensemble, as each of these three quantities are constants of the ensemble.
Basics.
In simple terms, the grand canonical ensemble assigns a probability to each distinct microstate given by the following exponential:
where is the number of particles in the microstate and is the total energy of the microstate. is Boltzmann's constant.
The number is known as the grand potential and is constant for the ensemble. However, the probabilities and will vary if different are selected. The grand potential serves two roles: to provide a normalization factor for the probability distribution (the probabilities, over the complete set of microstates, must add up to one); and, many important ensemble averages can be directly calculated from the function .
In the case where more than one kind of particle is allowed to vary in number, the probability expression generalizes to
where is the chemical potential for the first kind of particles, is the number of that kind of particle in the microstate, is the chemical potential for the second kind of particles and so on ( is the number of distinct kinds of particles). However, these particle numbers should be defined carefully (see the note on particle number conservation below).
Grand ensembles are apt for use when describing systems such as the electrons in a conductor, or the photons in a cavity, where the shape is fixed but the energy and number of particles can easily fluctuate due to contact with a reservoir (e.g., an electrical ground or a dark surface, in these cases). The grand canonical ensemble provides a natural setting for an exact derivation of the Fermi–Dirac statistics or Bose–Einstein statistics for a system of non-interacting quantum particles (see examples below).
Applicability.
The grand canonical ensemble is the ensemble that describes the possible states of an isolated system that is in thermal and chemical equilibrium with a reservoir (the derivation proceeds along lines analogous to the heat bath derivation of the normal canonical ensemble, and can be found in Reif). The grand canonical ensemble applies to systems of any size, small or large; it is only necessary to assume that the reservoir with which it is in contact is much larger (i.e., to take the macroscopic limit).
The condition that the system is isolated is necessary in order to ensure it has well-defined thermodynamic quantities and evolution. In practice, however, it is desirable to apply the grand canonical ensemble to describe systems that are in direct contact with the reservoir, since it is that contact that ensures the equilibrium. The use of the grand canonical ensemble in these cases is usually justified either 1) by assuming that the contact is weak, or 2) by incorporating a part of the reservoir connection into the system under analysis, so that the connection's influence on the region of interest is correctly modeled. Alternatively, theoretical approaches can be used to model the influence of the connection, yielding an open statistical ensemble.
Another case in which the grand canonical ensemble appears is when considering a system that is large and thermodynamic (a system that is "in equilibrium with itself"). Even if the exact conditions of the system do not actually allow for variations in energy or particle number, the grand canonical ensemble can be used to simplify calculations of some thermodynamic properties. The reason for this is that various thermodynamic ensembles (microcanonical, canonical) become equivalent in some aspects to the grand canonical ensemble, once the system is very large. Of course, for small systems, the different ensembles are no longer equivalent even in the mean. As a result, the grand canonical ensemble can be highly inaccurate when applied to small systems of fixed particle number, such as atomic nuclei.
Grand potential, ensemble averages, and exact differentials.
The partial derivatives of the function give important grand canonical ensemble average quantities:
"Exact differential": From the above expressions, it can be seen that the function has the exact differential
"First law of thermodynamics": Substituting the above relationship for into the exact differential of , an equation similar to the first law of thermodynamics is found, except with average signs on some of the quantities:
"Thermodynamic fluctuations": The variances in energy and particle numbers are
"Correlations in fluctuations": The covariances of particle numbers and energy are
Example ensembles.
The usefulness of the grand canonical ensemble is illustrated in the examples below. In each case the grand potential is calculated on the basis of the relationship
which is required for the microstates' probabilities to add up to 1.
Statistics of noninteracting particles.
Bosons and fermions (quantum).
In the special case of a quantum system of many "non-interacting" particles, the thermodynamics are simple to compute.
Since the particles are non-interacting, one can compute a series of single-particle stationary states, each of which represent a separable part that can be included into the total quantum state of the system.
For now let us refer to these single-particle stationary states as "orbitals" (to avoid confusing these "states" with the total many-body state), with the provision that each possible internal particle property (spin or polarization) counts as a separate orbital.
Each orbital may be occupied by a particle (or particles), or may be empty.
Since the particles are non-interacting, we may take the viewpoint that "each orbital forms a separate thermodynamic system".
Thus each orbital is a grand canonical ensemble unto itself, one so simple that its statistics can be immediately derived here. Focusing on just one orbital labelled , the total energy for a microstate of particles in this orbital will be , where is the characteristic energy level of that orbital. The grand potential for the orbital is given by one of two forms, depending on whether the orbital is bosonic or fermionic:
\Big) \\
 & = - kT \ln\Big(1 + e^{\frac{\mu - \epsilon_i}{k T}}\Big)
\end{align}</math>
In each case the value formula_13 gives the thermodynamic average number of particles on the orbital: the Fermi–Dirac distribution for fermions, and the Bose–Einstein distribution for bosons.
Considering again the entire system, the total grand potential is found by adding up the for all orbitals.
Indistinguishable classical particles.
In classical mechanics it is also possible to consider indistinguishable particles (in fact, indistinguishability is a prerequisite for defining a chemical potential in a consistent manner; all particles of a given kind must be interchangeable). We again consider placing multiple particles of the same kind into the same microstate of single-particle phase space, which we again call an "orbital". However, compared to quantum mechanics, the classical case is complicated by the fact that a microstate in classical mechanics does not refer to a single point in phase space but rather to an extended region in phase space: one microstate contains an infinite number of states, all distinct but of similar character. As a result, when multiple particles are placed into the same orbital, the overall collection of the particles (in the system phase space) does not count as one whole microstate but rather only a "fraction" of a microstate, because identical states (formed by permutation of identical particles) should not be overcounted. The overcounting correction factor is the factorial of the number of particles.
The statistics in this case take the form of an exponential power series
the value formula_15 corresponding to Maxwell–Boltzmann statistics.
Ionization of an isolated atom.
The grand canonical ensemble can be used to predict whether an atom prefers to be in a neutral state or ionized state.
An atom is able to exist in ionized states with more or fewer electrons compared to neutral. As shown below, ionized states may be thermodynamically preferred depending on the environment.
Consider a simplified model where the atom can be in a neutral state or in one of two ionized states (a detailed calculation also includes the degeneracy factors of the states):
Here and are the atom's ionization energy and electron affinity, respectively; is the local electrostatic potential in the vacuum nearby the atom, and is the electron charge.
The grand potential in this case is thus determined by
The quantity is critical in this case, for determining the balance between the various states. This value is determined by the environment around the atom.
If one of these atoms is placed into a vacuum box, then , the work function of the box lining material. Comparing the tables of work function for various solid materials with the tables of electron affinity and ionization energy for atomic species, it is clear that many combinations would result in a neutral atom, however some specific combinations would result in the atom preferring an ionized state: e.g., a halogen atom in a ytterbium box, or a cesium atom in a tungsten box. At room temperature this situation is not stable since the atom tends to adsorb to the exposed lining of the box instead of floating freely. At high temperatures, however, the atoms are evaporated from the surface in ionic form; this spontaneous surface ionization effect has been used as a cesium ion source.
At room temperature, this example finds application in semiconductors, where the ionization of a dopant atom is well described by this ensemble. In the semiconductor, the conduction band edge plays the role of the vacuum energy level (replacing ), and is known as the Fermi level. Of course, the ionization energy and electron affinity of the dopant atom are strongly modified relative to their vacuum values. A typical donor dopant in silicon, phosphorus, has ;
the value of in the intrinsic silicon is initially about , guaranteeing the ionization of the dopant.
The value of depends strongly on electrostatics, however, so under some circumstances it is possible to de-ionize the dopant.
Meaning of chemical potential, generalized "particle number".
In order for a particle number to have an associated chemical potential, it must be conserved during the internal dynamics of the system, and only able to change when the system exchanges particles with an external reservoir.
If the particles can be created out of energy during the dynamics of the system, then an associated term must not appear in the probability expression for the grand canonical ensemble. In effect, this is the same as requiring that for that kind of particle. Such is the case for photons in a black cavity, whose number regularly change due to absorption and emission on the cavity walls. (On the other hand, photons in a highly reflective cavity can be conserved and caused to have a nonzero .)
In some cases the number of particles is not conserved and the represents a more abstract conserved quantity:
On the other hand, in some cases a single kind of particle may have multiple conserved numbers:
Precise expressions for the ensemble.
The precise mathematical expression for statistical ensembles has a distinct form depending on the type of mechanics under consideration (quantum or classical), as the notion of a "microstate" is considerably different. In quantum mechanics, the grand canonical ensemble affords a simple description since diagonalization provides a set of distinct microstates of a system, each with well-defined energy and particle number. The classical mechanical case is more complex as it involves not stationary states but instead an integral over canonical phase space.
Quantum mechanical.
A statistical ensemble in quantum mechanics is represented by a density matrix, denoted by formula_17. The grand canonical ensemble is the density matrix
where is the system's total energy operator (Hamiltonian), is the system's total particle number operator for particles of type 1, is the total particle number operator for particles of type 2, and so on. is the matrix exponential operator. The grand potential is determined by the probability normalization condition that the density matrix has a trace of one, formula_19:
Note that for the grand ensemble, the basis states of the operators , , etc. are all states with "multiple particles" in Fock space, and the density matrix is defined on the same basis. Since the energy and particle numbers are all separately conserved, these operators are mutually commuting.
The grand canonical ensemble can alternatively be written in a simple form using bra–ket notation, since it is possible (given the mutually commuting nature of the energy and particle number operators) to find a complete basis of simultaneous eigenstates , indexed by , where , , and so on. Given such an eigenbasis, the grand canonical ensemble is simply
where the sum is over the complete set of states with state having total energy, particles of type 1, particles of type 2, and so on.
Classical mechanical.
In classical mechanics, a grand ensemble is instead represented by a joint probability density function defined over multiple phase spaces of varying dimensions, , where the and are the canonical coordinates (generalized momenta and generalized coordinates) of the system's internal degrees of freedom. The expression for the grand canonical ensemble is somewhat more delicate than the canonical ensemble since:
In a system of particles, the number of degrees of freedom depends on the number of particles in a way that depends on the physical situation. For example, in a three-dimensional gas of monoatoms , however in molecular gases there will also be rotational and vibrational degrees of freedom.
The probability density function for the grand canonical ensemble is:
where
Again, the value of is determined by demanding that is a normalized probability density function:
This integral is taken over the entire available phase space for the given numbers of particles.
Overcounting correction.
A well-known problem in the statistical mechanics of fluids (gases, liquids, plasmas) is how to treat particles that are similar or identical in nature: should they be regarded as distinguishable or not? In the system's equation of motion each particle is forever tracked as a distinguishable entity, and yet there are also valid states of the system where the positions of each particle have simply been swapped: these states are represented at different places in phase space, yet would seem to be equivalent.
If the permutations of similar particles are regarded to count as distinct states, then the factor above is simply . From this point of view, ensembles include every permuted state as a separate microstate. Although appearing benign at first, this leads to a problem of severely non-extensive entropy in the canonical ensemble, known today as the Gibbs paradox. In the grand canonical ensemble a further logical inconsistency occurs: the number of distinguishable permutations depends not only on how many particles are in the system, but also on how many particles are in the reservoir (since the system may exchange particles with a reservoir). In this case the entropy and chemical potential are non-extensive but also badly defined, depending on a parameter (reservoir size) that should be irrelevant.
To solve these issues it is necessary that the exchange of two similar particles (within the system, or between the system and reservoir) must not be regarded as giving a distinct state of the system. In order to incorporate this fact, integrals are still carried over full phase space but the result is divided by
which is the number of different permutations possible. The division by neatly corrects the overcounting that occurs in the integral over all phase space.
It is of course possible to include distinguishable "types" of particles in the grand canonical ensemble—each distinguishable type formula_26 is tracked by a separate particle counter formula_27 and chemical potential formula_28. As a result, the only consistent way to include "fully distinguishable" particles in the grand canonical ensemble is to consider every possible distinguishable type of those particles, and to track each and every possible type with a separate particle counter and separate chemical potential.


John A. Sanderson

John Adolph Sanderson (c.1909 – 11 February 1998) was president of the Optical Society of America in 1967. He was the former head of the optics division at Naval Research Labs and the Research and Education Officer for the Optical Society of America.
Born in Vardaman, Mississippi he gained an A.B. in 1928 and an A.M. in 1929 from the University of Mississippi, afterwards working as a teaching fellow at the university teaching physics and astronomy. He then gained a Ph.D in physics, specializing in optics, at Johns Hopkins University, staying on there for two years to teach physics and astronomy. In 1935 he transferred to the United States Naval Research Laboratory where he worked on a number of optical issues and projects. As superintendent of the Optics Division from 1950 he was involved in the optical measurement of nuclear explosions.
He was inducted as a Fellow of the American Physical Society in 1953. From 1965 to his retirement in 1971 he served on the board of the Optical Society.
He died at the age of 89 in Clemson, South Carolina in 1998. He had been married to Elizabeth and had at least one daughter.


Proper velocity

In relativity, proper velocity (also known as celerity) w of an object relative to an observer is the ratio between observer-measured displacement vector formula_1 and proper time elapsed on the clocks of the traveling object:
It is an alternative to ordinary velocity, the distance per unit time where both distance and time are measured by the observer.
The two types of velocity, ordinary and proper, are very nearly equal at low speeds. However, at high speeds proper velocity retains many of the properties that velocity loses in relativity compared with Newtonian theory.
For example, proper velocity equals momentum per unit mass at any speed, and therefore has no upper limit. At high speeds, as shown in the figure at right, it is proportional to an object's energy as well.
Proper velocity w can be related to the ordinary velocity v via the Lorentz factor "γ":
where "t" is coordinate time or "map time".
For unidirectional motion, each of these is also simply related to a traveling object's hyperbolic velocity angle or rapidity "η" by
Introduction.
In flat spacetime, proper velocity is the ratio between distance traveled relative to a reference map frame (used to define simultaneity) and proper time τ elapsed on the clocks of the traveling object. It equals the object's momentum p divided by its rest mass "m", and is made up of the space-like components of the object's four-vector velocity. William Shurcliff's monograph mentioned its early use in the Sears and Brehme text. Fraundorf has explored its pedagogical value while Ungar, Baylis and Hestenes have examined its relevance from group theory and geometric algebra perspectives. Proper velocity is sometimes referred to as celerity.
Unlike the more familiar coordinate velocity v, proper velocity is synchrony-free (does not require synchronized clocks) and is useful for describing both super-relativistic and sub-relativistic motion. Like coordinate velocity and unlike four-vector velocity, it resides in the three-dimensional slice of spacetime defined by the map frame. As shown below and in the example figure at right, proper-velocities even add as three vectors with rescaling of the out-of-frame component. This makes them more useful for map-based (e.g. engineering) applications, and less useful for gaining coordinate-free insight. Proper speed divided by lightspeed "c" is the hyperbolic sine of rapidity "η", just as the Lorentz factor "γ" is rapidity's hyperbolic cosine, and coordinate speed "v" over lightspeed is rapidity's hyperbolic tangent.
Imagine an object traveling through a region of spacetime locally described by Hermann Minkowski's flat-space metric equation . Here a reference map frame of yardsticks and synchronized clocks define map position x and map time "t" respectively, and the "d" preceding a coordinate means infinitesimal change. A bit of manipulation allows one to show that proper velocity where as usual coordinate velocity . Thus finite "w" ensures that "v" is less than lightspeed "c". By grouping "γ" with v in the expression for relativistic momentum p, proper velocity also extends the Newtonian form of momentum as mass times velocity to high speeds without a need for relativistic mass.
Proper velocity addition formula.
The proper velocity addition formula:
where formula_6 is the beta factor given by formula_7.
Hyperbolic velocity angle or rapidity.
or in terms of logarithms:
Applications.
Comparing velocities at high speed.
Proper velocity is useful for comparing the speed of objects with momentum per unit rest mass ("w") greater than lightspeed "c". The coordinate speed of such objects is generally near lightspeed, whereas proper velocity tells us how rapidly they are covering ground on "traveling-object clocks". This is important for example if, like some cosmic ray particles, the traveling objects have a finite lifetime. Proper velocity also clues us in to the object's momentum, which has no upper bound.
For example, a 45 GeV electron accelerated by the Large Electron–Positron Collider (LEP) at Cern in 1989 would have had a Lorentz factor γ of about 88,000 (45 GeV divided by the electron rest mass of 511 keV). Its coordinate speed "v" would have been about sixty four trillionths shy of lightspeed "c" at 1 lightsecond per "map" second. On the other hand, its proper speed would have been "w" = "γv" ~ 88,000 lightseconds per "traveler" second. By comparison the coordinate speed of a 250 GeV electron in the proposed International Linear Collider (ILC) will remain near "c", while its proper speed will significantly increase to ~489,000 lightseconds per traveler second.
Proper velocity is also useful for comparing relative velocities along a line at high speed. In this case
where A, B and C refer to different objects or frames of reference. For example, "w"AC refers to the proper speed of object A with respect to object C. Thus in calculating the relative proper speed, Lorentz factors multiply when coordinate speeds add.
Hence each of two electrons (A and C) in a head-on collision at 45 GeV in the lab frame (B) would see the other coming toward them at "v"AC ~ "c" and "w"AC = 88,0002(1 + 1) ~ 1.55×1010 lightseconds per traveler second. Thus from the target's point of view, colliders can explore collisions with much higher projectile energy and momentum per unit mass.
Proper velocity-based dispersion relations.
 Plotting "("γ" − 1) versus proper velocity" after multiplying the former by "mc"2 and the latter by mass "m", for various values of "m" yields a family of kinetic energy versus momentum curves that includes most of the moving objects encountered in everyday life. Such plots can for example be used to show where lightspeed, Planck's constant, and Boltzmann energy "kT" figure in.
To illustrate, the figure at right with log-log axes shows objects with the same kinetic energy (horizontally related) that carry different amounts of momentum, as well as how the speed of a low-mass object compares (by vertical extrapolation) to the speed after perfectly inelastic collision with a large object at rest. Highly sloped lines (rise/run = 2) mark contours of constant mass, while lines of unit slope mark contours of constant speed.
Objects that fit nicely on this plot are humans driving cars, dust particles in Brownian motion, a spaceship in orbit around the sun, molecules at room temperature, a fighter jet at Mach 3, one radio wave photon, a person moving at one lightyear per traveler year, the pulse of a 1.8 MegaJoule laser, a 250 GeV electron, and our observable universe with the blackbody kinetic energy expected of a single particle at 3 kelvin.
Unidirectional acceleration via proper velocity.
Proper acceleration at any speed is "the physical acceleration experienced locally by an object". In spacetime it is a three-vector acceleration with respect to the object's instantaneously varying free-float frame. Its magnitude α is the frame-invariant magnitude of that object's four-acceleration. Proper acceleration is also useful from the vantage point (or spacetime slice) of external observers. Not only may observers in all frames agree on its magnitude, but it also measures the extent to which an accelerating rocket "has its pedal to the metal".
In the unidirectional case i.e. when the object's acceleration is parallel or anti-parallel to its velocity in the spacetime slice of the observer, the "change in proper velocity is the integral of proper acceleration over map time" i.e. for constant "α". At low speeds this reduces to the well-known relation between coordinate velocity and coordinate acceleration times map time, i.e. . For constant unidirectional proper acceleration, similar relationships exist between rapidity "η" and elapsed proper time Δ"τ", as well as between Lorentz factor "γ" and distance traveled Δ"x". To be specific:
where as noted above the various velocity parameters are related by
These equations describe some consequences of accelerated travel at high speed. For example, imagine a spaceship that can accelerate its passengers at 1 g (or 1.03 lightyears/year2) halfway to their destination, and then decelerate them at 1 g for the remaining half so as to provide earth-like artificial gravity from point A to point B over the shortest possible time. For a map distance of ΔxAB, the first equation above predicts a midpoint Lorentz factor (up from its unit rest value) of γmid=1+α(ΔxAB/2)/c2. Hence the round-trip time on traveler clocks will be Δτ = 4(c/α)cosh−1[γmid], during which the time elapsed on map clocks will be Δt = 4(c/α)sinh[cosh−1[γmid]].
This imagined spaceship could offer round trips to Proxima Centauri lasting about 7.1 traveler years (~12 years on earth clocks), round trips to the Milky Way's central black hole of about 40 years (~54,000 years elapsed on earth clocks), and round trips to Andromeda Galaxy lasting around 57 years (over 5 million years on earth clocks). Unfortunately, while rocket accelerations of 1 g can easily be achieved, they cannot be sustained over long periods of time.


Barbara Kraus

Barbara Kraus is an Austrian physicist specializing in quantum information, quantum entanglement, and quantum key distribution.
She is a University Professor of Physics at the University of Innsbruck.
Education and Career.
Kraus is originally from Innsbruck. She studied mathematics and physics at the University of Innsbruck, earning diplomas in mathematics and physics and a PhD in physics, completed in 2003. After postdoctoral research at the Max Planck Institute of Quantum Optics, the University of Geneva, and University of Innsbruck, she became an assistant professor in Innsbruck in 2010, and earned her habilitation there in 2012. She became full professor in 2019.
Research.
Kraus is best known for her work in quantum information and especially in entanglement theory. Together with her coworkers she developed criteria to decide whether a quantum state is separable or entangled and showed how to construct optimal entanglement witnesses and studied the creation of entanglement by unitary quantum gates and dissipative processes. In 2010 she showed how to decide whether two pure quantum states of a many-particle system are equivalent to each other in terms of entanglement. More recently she introduced the notion of "maximally entangled sets" as a new concept generalizing maximally entangled "states" to the case of considering entanglement between more than two systems (multipartite entanglement). In the field of quantum cryptography, she studied the security of key-distribution protocols and the achievable secret-key rates. Among other results, she and her collaborators gave an influential information-theoretic security proof for the security of a quantum key distribution protocol
Recognition.
Kraus won a Start-Preis from the Austrian Science Fund in 2010. She was the 2011 winner of the Ludwig Boltzmann Prize of the Austrian Physical Society, and the 2013 winner of the Lieben Prize of the Austrian Academy of Sciences for her work on many-body entanglement. She became a member of the Young Academy of the Austrian Academy of Sciences in 2014.


Aleksandr Andronov

Aleksandr Aleksandrovich Andronov (; , Moscow – October 31, 1952, Gorky) was a Soviet physicist and member of the Soviet Academy of Sciences (1946). He worked extensively on the theory of stability of dynamical systems, introducing (together with Lev Pontryagin) the notion of structural stability. In that context, he also contributed to the mathematical theory of self-oscillation (a term that he coined) by establishing a link between the generation of oscillations and the theory of Lyapunov stability. He developed the comprehensive theory of self-oscillations by linking it with the qualitative theory of differential equations, topology, and with the general theory of stability of motion. The crater Andronov on the Moon is named after him.


AIP Advances

AIP Advances is an open-access peer-reviewed scientific mega journal published by the American Institute of Physics. It was established in March 2011. It covers all aspects of physics, both experimental and theoretical.
Submissions are peer-reviewed to assess accuracy and originality, while impact, timeliness, and interest are judged a posteriori through online discussion and ranking tools. All articles are published under a Creative Commons License, with the author retaining the copyright and paying a publication fee.
The editors-in-chief are Vincent H. Crespi (Pennsylvania State University), Bernard S. Gerstman (Florida International University), A. T. Charlie Johnson (University of Pennsylvania), Masaaki Tanaka (University of Tokyo), and Enge G. Wang (Peking University). The journal is abstracted and indexed by the Science Citation Index Expanded and Current Contents/Physical, Chemical & Earth Sciences. According to the "Journal Citation Reports", the journal has a 2018 impact factor of 1.579.


Sciography

Sciography, also spelled sciagraphy or skiagraphy (), is a branch of science of the perspective dealing with the projection of shadows, or delineation of an object in perspective with its gradations of light and shade. One of the major professional fields that use this technique is the architectural field. In architecture it is defined as a study of shades and shadows cast by simple architectural forms on plane surfaces.
In general sciography the light source is imagined as the sun inclined at 45 degrees to both vertical plane and horizontal plane coming from left hand side. The resultant shadow is then drawn.


Elmar (lens)

The name Elmar is used by Leica to designate camera lenses of four elements that have a maximum aperture of f/3.98 or f/4.0.
History.
The Elmar lenses originally had a maximum aperture of f/3.5. These lenses were derived from a 50 mm f/3.5 Elmax lens first produced in 1925. The name is a combination of Ernst Leitz and Max Berak.
Description.
Elmar lenses variously has a maximum f-number of f/2.8 or f/3.4 or f/3.8 or f/4. Currently the Elmar lenses have a maximum aperture of f/3.8 or f/4, as in the Elmar-M 24 mm f/3.8 and Tri-Elmar-M 16-18-21 mm f/4. The name Elmar is sometimes combined with: Super, Tele, APO, Macro or Vario.
Market positions.
Elmar lenses are comparatively slow. As a result they tend to be smaller and lighter than faster lenses of the same focal length.


Luciano Guerriero

Luciano Guerriero is an Italian physicist. He earned his degree in physics at University of Padua in 1952 and is now based in Bari University. Between 1988 and 1992 He headed the Italian Space Agency and has set up programs of collaboration with NASA such as the Cassini–Huygens mission to Saturn.
There's an asteroid (15005 Guerriero) named after Luciano Guerriero.
Luciano Guerriero has been P.I for the European project LEWIS for a landslide early warning system based on space data from SAR satellites.