UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Gondolo, PaoloDark Stars: Död och ÅteruppståndelseThe first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in the univers...Dark stars; WIMP; Weakly interacting massive particles2009
2 Gondolo, PaoloDark stars: BegynnelsenThe first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in the univers...Dark stars; WIMP; Weakly interacting massive particles; Annihilations2009
3 Gondolo, PaoloDark stars: dark matter in the first stars leads to a new phase of stellar evolutionThe _x000C_first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the fi_x000C_rst stars...Dark stars; WIMP; Weakly interacting massive particles2008-06
4 DeTar, CarletonTopological susceptibility with the improved Asqtad actionAs a test of the chiral properties of the improved Asqtad (staggered fermion) action, we have been measuring the topological susceptibility as a function of quark masses for 2 + 1 dynamical flavors. We report preliminary results, which show reasonable agreement with leading order chiral perturbatio...Topological cbarge; Staggered fermions2003-05
5 Gondolo, PaoloPhysics of the very early universe: what can we learn from cosmological observations?Cosmological observations are starting to probe the evolution of the Universe before nucleosynthesis. The observed fluctuations in the cosmic microwave background and in the distribution of matter can be traced back to their origin during inflation, and the inflaton potential has begun to be unrave...Neutralinos; Inflatons; Moduli fields2006
6 Gondolo, PaoloAxion cold dark matter in nonstandard cosmologiesWe study the parameter space of cold dark matter axions in two cosmological scenarios with nonstandard thermal histories before big bang nucleosynthesis: the low-temperature reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allow...2010-01-01
7 Sokolsky, PierreHighest-energy cosmic raysWhat in the cosmos can possibly be accelerating protons to 1020 electron volts and beyond? And how can they preserve such extreme energies while plowing through the cosmic microwave background on their way to us?Energy spectrum; GZK cutoff; Atmospheric fluorescence1998
8 DeTar, CarletonTopological susceptibility with the improved Asqtad actionChiral perturbation theory predicts that in quantum chromodynamics light dynamical quarks suppress the topological (instanton) susceptibility.We investigate this suppression through direct numerical simulation using the Asqtad improved lattice fermion action. This action holds promise for carrying...Chiral perturbation; Staggered fermions2003-12
9 Efros, Alexei L.Sensor-based distributed control scheme for mobile robotsIn this paper we present a sensor-based distributed control scheme for mobile robots. This scheme combines centralized and decentralized control strategies. A server-client model is used to implement this scheme where the server is a process that caries out the commands to be executed, and each clie...Sensor-based; Distributed control scheme1995
10 Saam, BrianWall relaxation of 3He in spin-exchange cellsThe 3He longitudinal spin-relaxation rate T1-1 is crucial for production of highly polarized 3He by spin-exchange optical pumping. We show that T1-1 is increased by a factor of 2-20 solely by exposure of spin-exchange cells to a few-kG magnetic field. The original T1-1 can be restored by degaussing ...Wall relaxation; Spin-exchange cells; 3He; Longitudinal spin-relaxation; Spin-exchange optical pumping; SEOP; Hyperpolarized 3He; Surface magnetism; Glass cells2001-09
11 Gondolo, PaoloSection on prospects for dark matter detection of the white paper on the Status and future of ground-based TeV gamma-ray astronomyThis is a report on the findings of the dark matter science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed sec...Annihilations; Dwarf spheroidal2008
12 Gondolo, PaoloFluid interpretation of Cardassian expansionA fluid interpretation of Cardassian expansion is developed. Here, the Friedmann equation takes the form H2=g(ρM) where ρM contains only matter and radiation ~no vacuum!. The function g(ρM) returns to the usual 8πM /(3mpl 2 ) during the early history of the Universe, but takes a different form...Cardassian expansion; Friedmann equation2003-09
13 Symko, Orest GeorgeMagnetic memory of oil paintingsThe color in oil paints is obtained sometimes from magnetic minerals. This fact implies that oil paintings could present an intrinsic magnetization. Magnetic imaging of an oil painting consists in the measurement of magnetic flux related to the magnetization of the painting. In this report results o...Magnetic memory; Oil paintings; Authentication2007
14 Symko, Orest GeorgeEnergy conversion using thermoacoustic devicesThermoacoustic engines offer the possibility for simple and efficient energy convmiondevices. They can be prime movers where heat produces sound or heat pumps and refrigerators where sound pump heat. An important element in such engines is the secondary thermodynamic medium, the stack which provides...Thermoacoustic devices; Thermoacoustics1999
15 Gondolo, PaoloDUSEL theory white paperThe scientific case for a Deep Underground Science and Engineering Laboratory [DUSEL] located at the Homestake mine in Lead, South Dakota is exceptional. The site of this future laboratory already claims a discovery for the detection of solar neutrinos, leading to a Nobel Prize for Ray Davis. Moreov...DUSEL; Deep Underground Science and Engineering Laboratory; Proton decay2008
16 Wu, Yong-ShiManifestations of Berry's topological phase for the photonRecently, Berry recognized in quantum mechanics a topological phase factor arising from the adiabatic transport of a system around a closed circuit, which is essentially the Aharonov-Bohm effect in parameter space. Here we consider manifestations of this phase factor for a photon in a state of adia...Aharonov-Bohm effect; Optical fibers; Waveguide1986-08
17 Symko, Orest GeorgeSize considerations in interfacing thermoacoustic coolers with electronicsSmall thermoacoustic coolers heat pumps show much promise for heat management in microcircuits, especially since they can be miniaturized for interfacing with circuits. Usually they are operated in the resonant mode with sound pumping heat; the device dimensions are reduced when the acoustic pump fr...Thermoacoustic coolers; Heat management; Microcircuits; Miniturization2002
18 Gondolo, PaoloThe effect of quark interactions on dark matter kinetic decoupling and the mass of the smallest dark halosThe kinetic decoupling of dark matter (DM) from the primordial plasma sets the size of the first and smallest DM halos. Studies of the DM kinetic decoupling have hitherto mostly neglected interactions between the DM and the quarks in the plasma. Here we illustrate their importance using two framewor...2012-01-01
19 DeTar, CarletonRole of baryons in chiral-symmetry restoration at high temperatureTo help provide insight into the apparent remarkable rise in baryon susceptibility at the high-temperature phase transition in QCD, we study the three-dimensional lattice SU(2) chiral model at finite temperature. The purpose of this study is to determine the extent to which a rising susceptibility i...Chiral model; Chiral symmetry; Quark plasma; Skyrmions; Phase transitions1990-07
20 DeTar, CarletonCritical behavior in Nt=4 staggered fermion thermodynamicsQuantum chromodynamics with two zero mass flavors is expected to exhibit a phase transition with O(4) critical behavior. Fixing the universality class is important for phenomenology and for facilitating the extrapolation of simulation data to physical quark mass values. Other groups have reported r...Staggered fermions; Phase transitions2000-01
21 DeTar, CarletonCritical behavior in Nt=4 staggered fermion thermodynamicsQuantum chromodynamics with two zero mass flavors is expected to exhibit a phase transition with O(4) critical behavior. Fixing the universality class is important for phenomenology and for facilitating the extrapolation of simulation data to physical quark mass values. Other groups have reported r...Staggered fermions; Phase transitions; Quark-gluon plasma; Chiral symmetry2000-01
22 Kieda, David B.High resolution charge measurements of UH cosmic ray nuclei using a direct imaging Cherenkov ground-based observatoryThe accurate determination of the elemental composition of cosmic rays at high energies is expected to provide crucial clues on the origin of these particles. Here we discuss a technique that has become possible through the use of modern ground-based Cherenkov imaging detectors. We combine a measure...Cherenkov light; Quark star; UH nuclei; Magnetic monopole2003
23 Dawson, KyleSubaru FOCAS spectroscopic observations of high-redshift supernovaeWe present spectra of high-redshift supernovae (SNe) that were taken with the Subaru low-resolution optical spectrograph, FOCAS. These SNe were found in SN surveys with Suprime-Cam on Subaru, the CFH12k camera on the Canada-France-Hawaii Telescope, and the Advanced Camera for Surveys on the Hubble S...2010-01-01
24 Gondolo, PaoloEffects of the Sagittarius dwarf tidal stream on dark matter detectorsThe Sagittarius dwarf tidal stream may be showering dark matter onto the solar neighborhood, which can change the results and interpretation of direct detection searches for weakly interacting massive particles (WIMPs). Stars in the stream may already have been detected in the solar neighborhood, an...Sagittarius dwarf galaxy; Sgr stream; WIMP; Weakly interacting massive particles2004-03
25 Saam, BrianLow-field orientation dependence of 3He relaxation in spin-exchange cellsWe have observed a significant dependence of 3He longitudinal relaxation times in glass spin-exchange optical pumping (SEOP) cells due only to the physical orientation of the cell in a 3 mT (30 G) applied magnetic field. The cells had no previous exposure to higher fields or were thoroughly degau...Spin-exchange optical pumping; SEOP; 3He; Hyperpolarized noble gases; Longitudinal spin-relaxation; MEOP; Low-field orientation2004-02
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