Browsing by Publisher "Amer Physical Soc."
Now showing items 110 of 10

Bound free electronpositron pair production accompanied by giant dipole resonances
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Publisher and Date:(Amer Physical Soc., 2011)At the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) for example virtual photons produce many particles. At small impact parameters where the colliding nuclei make peripheral collisions photon fluxes are very large and these are responsible for the multiple photonuclear interactions. Free pair productions bound free pair productions and nuclear Coulomb excitations are important examples of such interactions and these processes play important roles in the beam luminosity ...

Boundfree electronpositron pair production in relativistic heavyion collisions
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Publisher and Date:(Amer Physical Soc., 2009)The boundfree electronpositron pair production is considered for relativistic heavy ion collisions. In particular cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the relativistic heavy ion collider and the large hadron colliders. In the framework of perturbation theory we applied Monte Carlo integration techniques to compute the lowestorder Feynman diagrams ...

Coulomb corrections in the leptonpair production in ultrarelativistic nuclear collisions
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Publisher and Date:(Amer Physical Soc., 2005)We solve the perturbative electronpositron pair production exactly by calculating the secondorder Feynman diagrams. We compare our result with Born methods that include Coulomb corrections. We find that a smallmomentum approximation is not adequate to obtain exact Coulomb corrections and higherorder terms should also be included. We also compare the impact parameter dependence cross sections.

Crossover from Vibrational to Rotational Collectivity in Heavy Nuclei in the ShellModel Monte Carlo Approach
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Publisher and Date:(Amer Physical Soc., 2013)Heavy nuclei exhibit a crossover from vibrational to rotational collectivity as the number of neutrons or protons increases from shell closure towards midshell but the microscopic description of this crossover has been a major challenge. We apply the shell model Monte Carlo approach to families of eveneven samarium and neodymium isotopes and identify a microscopic signature of the crossover from vibrational to rotational collectivity in the lowtemperature behavior of < J(2)>(T) where J is the ...

Devil's staircase continuum in the chiral clock spin glass with competing ferromagneticantiferromagnetic and leftright chiral interactions
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Publisher and Date:(Amer Physical Soc., 2017)The chiral clock spinglass model with q = 5 states with both competing ferromagneticantiferromagnetic and leftright chiral frustrations is studied in d = 3 spatial dimensions by renormalizationgroup theory. The global phase diagram is calculated in temperature antiferromagnetic bond concentration p random chirality strength and rightchirality concentration c. The system has a ferromagnetic phase a multitude of different chiral phases a chiral spinglass phase and a critical (algebraically) ...

Lower lowercritical spinglass dimension from quenched mixedspatialdimensional spin glasses
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Publisher and Date:(Amer Physical Soc., 2018)By quenchedrandomly mixing local units of different spatial dimensionalities we have studied Ising spinglass systems on hierarchical lattices continuously in dimensionalities 1 <= d <= 3. The global phase diagram in temperature antiferromagnetic bond concentration and spatial dimensionality is calculated. We find that as dimension is lowered the spinglass phase disappears to zero temperature at the lowercritical dimension d(c) = 2.431. Our system being a physically realizable system this sets ...

Maximally random discretespin systems with symmetric and asymmetric interactions and maximally degenerate ordering
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Publisher and Date:(Amer Physical Soc., 2018)Discretespin systems with maximally random nearestneighbor interactions that can be symmetric or asymmetric ferromagnetic or antiferromagnetic including offdiagonal disorder are studied for the number of states q = 34 in d dimensions. We use renormalizationgroup theory that is exact for hierarchical lattices and approximate (MigdalKadanoff) for hypercubic lattices. For all d > 1 and all nonmfimte temperatures the system eventually renormalizes to a random single state thus signaling q x q ...

Multifaceted Dynamics of Janus Oscillator Networks
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Publisher and Date:(Amer Physical Soc., 2019)Recent research has led to the discovery of fundamental new phenomena in network synchronization including chimera states explosive synchronization and asymmetryinduced synchronization. Each of these phenomena has thus far been observed only in systems designed to exhibit that one phenomenon which raises the questions of whether they are mutually compatible and if so under what conditions they cooccur. Here we introduce a class of remarkably simple oscillator networks that concurrently exhibit ...

Nuclear state densities of oddmass heavy nuclei in the shell model Monte Carlo approach
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Publisher and Date:(Amer Physical Soc., 2015)The shell model Monte Carlo (SMMC) approach enables the microscopic calculation of nuclear state densities in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization techniques. However it has been difficult to calculate accurate state densities of oddmass heavy nuclei as a function of excitation energy. This is because of a sign problem that arises from the projection on an odd number of particles at low temperatures making it difficult ...

Phase transitions between different spinglass phases and between different chaoses in quenched random chiral systems
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Publisher and Date:(Amer Physical Soc., 2017)The leftright chiral and ferromagneticantiferromagnetic doublespinglass clock model with the crucially even number of states q = 4 and in three dimensions d = 3 has been studied by renormalizationgroup theory. We find for the first time to our knowledge four spinglass phases including conventional chiral and quadrupolar spinglass phases and phase transitions between spinglass phases. The chaoses in the different spinglass phases and in the phase transitions of the spinglass phases with ...