phase space distribution
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2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Tarak Nath Maity ◽  
Tirtha Sankar Ray ◽  
Sambo Sarkar

AbstractThe dark matter direct detection rates are highly correlated with the phase space distribution of dark matter particles in our galactic neighbourhood. In this paper we make a systematic study of the impact of astrophysical uncertainties on electron recoil events at the direct detection experiments with Xenon and semiconductor detectors. We find that within the standard halo model there can be up to $$ \sim 50\%$$ ∼ 50 % deviation from the fiducial choice in the exclusion bounds from these observational uncertainties. For non-standard halo models we report a similar deviation from the fiducial standard halo model when fitted with recent cosmological N-body simulations while even larger deviations are obtained in case of the observational uncertainties.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Xiao-Li Luo ◽  
Jian-Hua Gao

Abstract We derive the chiral kinetic equation in 8 dimensional phase space in non- Abelian SU(N) gauge field within the Wigner function formalism. By using the “covariant gradient expansion”, we disentangle the Wigner equations in four-vector space up to the first order and find that only the time-like component of the chiral Wigner function is independent while other components can be explicit derivative. After further decomposing the Wigner function or equations in color space, we present the non-Abelian covariant chiral kinetic equation for the color singlet and multiplet phase-space distribution functions. These phase-space distribution functions have non-trivial Lorentz transformation rules when we define them in different reference frames. The chiral anomaly from non-Abelian gauge field arises naturally from the Berry monopole in Euclidian momentum space in the vacuum or Dirac sea contribution. The anomalous currents as non-Abelian counterparts of chiral magnetic effect and chiral vortical effect have also been derived from the non-Abelian chiral kinetic equation.


2021 ◽  
Author(s):  
Jan Grzesik

<div> We examine herein a simple model for the evolution in time of the pressure which a suddenly vaporized, ablating layer exerts upon the subjacent body. The model invokes a plausible construct of surface material instantaneously thrust into a gaseous regime governed by a Maxwell-Boltzmann phase space distribution. The surface pressure <i>per se</i> is gotten by computing the time rate of change of the momentum per unit area which the retrograde molecules, and only those, transfer through impact/reflection to the unvaporized body below. An explicit pressure formula, one alluding to the variable gas temperature within the vaporized layer, is obtained as a single quadrature requiring numerical integra- tion at finite times past the onset of impact. Limiting, null pressure values, both close-in and in pulse aftermath, can nevertheless be extracted in analytic terms, confirming in particular the indispensable asymptotic evanescence. A universal formula in dimensionless variables is given for pressure versus time, both suitably normalized.</div>


2021 ◽  
Author(s):  
Jan Grzesik

<div> We examine herein a simple model for the evolution in time of the pressure which a suddenly vaporized, ablating layer exerts upon the subjacent body. The model invokes a plausible construct of surface material instantaneously thrust into a gaseous regime governed by a Maxwell-Boltzmann phase space distribution. The surface pressure <i>per se</i> is gotten by computing the time rate of change of the momentum per unit area which the retrograde molecules, and only those, transfer through impact/reflection to the unvaporized body below. An explicit pressure formula, one alluding to the variable gas temperature within the vaporized layer, is obtained as a single quadrature requiring numerical integra- tion at finite times past the onset of impact. Limiting, null pressure values, both close-in and in pulse aftermath, can nevertheless be extracted in analytic terms, confirming in particular the indispensable asymptotic evanescence. A universal formula in dimensionless variables is given for pressure versus time, both suitably normalized.</div>


Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1175
Author(s):  
Fang Feng ◽  
Gang Lei

In this research, we studied the interaction between the ultra-intense laser and multiple copper layers covered with multiple hydrogen layers. The research conditions are based on the symmetric and asymmetric structure of multilayer copper and hydrogen. It was found that the acceleration obtained from the first copper and hydrogen layer plasma was higher and occurred earlier than the second copper and hydrogen layer plasma. We investigated the spatial distribution and phase-space distribution of copper electrons, copper ions, hydrogen electrons, and hydrogen protons with different widths of the front hydrogen layer and the front copper layer, respectively. Theoretical simulations show that when the ultra-intense laser was irradiated in multiple copper layers coated with multiple hydrogen layers targets, some plasma phase-space distribution varied clearly in the different thicknesses of the first hydrogen layer or first copper layer, while some plasma were not influenced by the thickness of these two layers.


2021 ◽  
Vol 154 (9) ◽  
pp. 094116
Author(s):  
Luca Maffioli ◽  
Nathan Clisby ◽  
Federico Frascoli ◽  
B. D. Todd

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
F. Becattini ◽  
M. Buzzegoli ◽  
A. Palermo

Abstract We derive a general exact form of the phase space distribution function and the thermal expectation values of local operators for the free quantum scalar field at equilibrium with rotation and acceleration in flat space-time without solving field equations in curvilinear coordinates. After factorizing the density operator with group theoretical methods, we obtain the exact form of the phase space distribution function as a formal series in thermal vorticity through an iterative method and we calculate thermal expectation values by means of analytic continuation techniques. We separately discuss the cases of pure rotation and pure acceleration and derive analytic results for the stress-energy tensor of the massless field. The expressions found agree with the exact analytic solutions obtained by solving the field equation in suitable curvilinear coordinates for the two cases at stake and already — or implicitly — known in literature. In order to extract finite values for the pure acceleration case we introduce the concept of analytic distillation of a complex function. For the massless field, the obtained expressions of the currents are polynomials in the acceleration/temperature ratios which vanish at 2π, in full accordance with the Unruh effect.


Author(s):  
Doogesh Kodi Ramanah ◽  
Radosław Wojtak ◽  
Nikki Arendse

Abstract We present a simulation-based inference framework using a convolutional neural network to infer dynamical masses of galaxy clusters from their observed 3D projected phase-space distribution, which consists of the projected galaxy positions in the sky and their line-of-sight velocities. By formulating the mass estimation problem within this simulation-based inference framework, we are able to quantify the uncertainties on the inferred masses in a straightforward and robust way. We generate a realistic mock catalogue emulating the Sloan Digital Sky Survey (SDSS) Legacy spectroscopic observations (the main galaxy sample) for redshifts z ≲ 0.09 and explicitly illustrate the challenges posed by interloper (non-member) galaxies for cluster mass estimation from actual observations. Our approach constitutes the first optimal machine learning-based exploitation of the information content of the full 3D projected phase-space distribution, including both the virialized and infall cluster regions, for the inference of dynamical cluster masses. We also present, for the first time, the application of a simulation-based inference machinery to obtain dynamical masses of around 800 galaxy clusters found in the SDSS Legacy Survey, and show that the resulting mass estimates are consistent with mass measurements from the literature.


2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Anja Butter ◽  
Tilman Plehn ◽  
Ramon Winterhalder

Subtracting event samples is a common task in LHC simulation and analysis, and standard solutions tend to be inefficient. We employ generative adversarial networks to produce new event samples with a phase space distribution corresponding to added or subtracted input samples. We first illustrate for a toy example how such a network beats the statistical limitations of the training data. We then show how such a network can be used to subtract background events or to include non-local collinear subtraction events at the level of unweighted 4-vector events.


2020 ◽  
Vol 894 (1) ◽  
pp. 10 ◽  
Author(s):  
Zhao-Zhou Li ◽  
Yong-Zhong Qian ◽  
Jiaxin Han ◽  
Ting S. Li ◽  
Wenting Wang ◽  
...  

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