Journal articles: 'Pre-Thermalization'

1

Kaminishi, Eriko, Takashi Mori, Tatsuhiko N. Ikeda, and Masahito Ueda. "Entanglement pre-thermalization in a one-dimensional Bose gas." Nature Physics 11, no. 12 (September 28, 2015): 1050–56. http://dx.doi.org/10.1038/nphys3478.

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Rajak, Atanu, Roberta Citro, and Emanuele G. Dalla Torre. "Stability and pre-thermalization in chains of classical kicked rotors." Journal of Physics A: Mathematical and Theoretical 51, no. 46 (October 22, 2018): 465001. http://dx.doi.org/10.1088/1751-8121/aae294.

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Wilkin, Francis P., Jorge Cantó, and Alex C. Raga. "On the Energetics and Momentum Distribution of Bow Shocks and Colliding Winds." Symposium - International Astronomical Union 182 (1997): 343–52. http://dx.doi.org/10.1017/s0074180900061763.

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We discuss recent progress in analytic modeling of stellar wind bow shocks and colliding winds. For thin, radiative shocked layers in steady-state, the shape of the layer as well as its internal flux of mass and momentum are found from the conservation laws of mass, momentum and angular momentum. For the case that the shocked gas is well-mixed, the velocity distribution and mass column density of shocked material are also obtained. These solutions are extended to the problem of a jet bow shock, treated as a non-isotropic “wind” interacting with the ambient medium. We also examine the shell energetics for these simple analytic models. The constraint of conservation of momentum leads to an upper limit to the efficiency of thermalization and radiation of the pre-shock wind kinetic energy. Calculations are presented of this thermalization rate as a function of the input momentum rates of the pre-shock winds.

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Masalskyi, O., and J. Gradauskas. "Effect of pre-thermalization of hot carriers on the photovoltage in solar cells." Ukrainian Journal of Physical Optics 23, no. 3 (2022): 117–25. http://dx.doi.org/10.3116/16091833/23/3/117/2022.

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Creamer, S. C., P. C. Rice-Evans, G. A. Gledhill, and J. D. Collins. "Evidence of pre-thermalization trapping of positrons in neutron-irradiated silicon-doped gallium arsenide." Philosophical Magazine B 63, no. 4 (April 1991): 923–30. http://dx.doi.org/10.1080/13642819108205547.

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Eskola, Kari J. "Pre-Thermalization Dynamics: Initial Conditions for QGP at the LHC and RHIC from Perturbative QCD." Progress of Theoretical Physics Supplement 129 (1997): 1–10. http://dx.doi.org/10.1143/ptps.129.1.

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Heitmann, Tjark, Jonas Richter, Dennis Schubert, and Robin Steinigeweg. "Selected applications of typicality to real-time dynamics of quantum many-body systems." Zeitschrift für Naturforschung A 75, no. 5 (May 26, 2020): 421–32. http://dx.doi.org/10.1515/zna-2020-0010.

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AbstractLoosely speaking, the concept of quantum typicality refers to the fact that a single pure state can imitate the full statistical ensemble. This fact has given rise to a rather simple but remarkably useful numerical approach to simulate the dynamics of quantum many-body systems, called dynamical quantum typicality (DQT). In this paper, we give a brief overview of selected applications of DQT, where particular emphasis is given to questions on transport and thermalization in low-dimensional lattice systems like chains or ladders of interacting spins or fermions. For these systems, we discuss that DQT provides an efficient means to obtain time-dependent equilibrium correlation functions for comparatively large Hilbert-space dimensions and long time scales, allowing the quantitative extraction of transport coefficients within the framework of, e. g., linear response theory (LRT). Furthermore, it is discussed that DQT can also be used to study the far-from-equilibrium dynamics resulting from sudden quench scenarios, where the initial state is a thermal Gibbs state of the pre-quench Hamiltonian. Eventually, we summarize a few combinations of DQT with other approaches such as numerical linked cluster expansions or projection operator techniques. In this way, we demonstrate the versatility of DQT.

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Fu, Dianzheng, Tianji Yang, Yize Huang, and Yiming Tong. "Integrated Optimization for Biofuel Management Associated with a Biomass-Penetrated Heating System under Multiple and Compound Uncertainties." Energies 15, no. 15 (July 26, 2022): 5406. http://dx.doi.org/10.3390/en15155406.

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The biofuel management of a biofuel-penetrated district heating system is complicated due to its association with multiple and polymorphic uncertainties. To handle uncertainties and system dynamic complexities, an inexact two-stage compound-stochastic mixed-integer programming technique is proposed, innovatively based on the integration of different uncertain optimization approaches. The proposed technique can not only address the inexact recourse problems sourced from multiple and compound uncertainties existing in the pre-regulated biofuel supply–demand match mode, but can also quantitatively analyze the conflicts between the economic target that minimizes the system cost and the risk preference that maximizes the heating service satisfaction. The developed model is applied to a real-world biofuel management case study of a district heating system to obtain the optimal biofuel management schemes subject to supply–demand, policy requirement constraints, and the financial minimization objective. The results indicate that biofuel allocation and expansion schemes are sensitive to the multiple and compound uncertainty inputs, and the corresponding biofuel-deficit change trends of three heat sources are obviously distinct with the system’s condition, varying due to the complicated interactions of the system’s components. Beyond that, a potential trade-off relationship between the heating cost and the constraint-violation risk can be obtained by observing system responses with thermalization coefficient varying.

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Messias, Andresa, Denys E. S. Santos, Frederico J. S. Pontes, Filipe S. Lima, and Thereza A. Soares. "Out of Sight, Out of Mind: The Effect of the Equilibration Protocol on the Structural Ensembles of Charged Glycolipid Bilayers." Molecules 25, no. 21 (November 4, 2020): 5120. http://dx.doi.org/10.3390/molecules25215120.

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Molecular dynamics (MD) simulations represent an essential tool in the toolbox of modern chemistry, enabling the prediction of experimental observables for a variety of chemical systems and processes and majorly impacting the study of biological membranes. However, the chemical diversity of complex lipids beyond phospholipids brings new challenges to well-established protocols used in MD simulations of soft matter and requires continuous assessment to ensure simulation reproducibility and minimize unphysical behavior. Lipopolysaccharides (LPS) are highly charged glycolipids whose aggregation in a lamellar arrangement requires the binding of numerous cations to oppositely charged groups deep inside the membrane. The delicate balance between the fully hydrated carbohydrate region and the smaller hydrophobic core makes LPS membranes very sensitive to the choice of equilibration protocol. In this work, we show that the protocol successfully used to equilibrate phospholipid bilayers when applied to complex lipopolysaccharide membranes occasionally leads to a small expansion of the simulation box very early in the equilibration phase. Although the use of a barostat algorithm controls the system dimension and particle distances according to the target pressure, fluctuation in the fleeting pressure occasionally enables a few water molecules to trickle into the hydrophobic region of the membrane, with spurious solvent buildup. We show that this effect stems from the initial steps of NPT equilibration, where initial pressure can be fairly high. This can be solved with the use of a stepwise-thermalization NVT/NPT protocol, as demonstrated for atomistic MD simulations of LPS/DPPE and lipid-A membranes in the presence of different salts using an extension of the GROMOS forcefield within the GROMACS software. This equilibration protocol should be standard procedure for the generation of consistent structural ensembles of charged glycolipids starting from atomic coordinates not previously pre-equilibrated. Although different ways to deal with this issue can be envisioned, we investigated one alternative that could be readily available in major MD engines with general users in mind.

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Gelis, François. "Initial state and thermalization in the Color Glass Condensate framework." International Journal of Modern Physics E 24, no. 10 (October 2015): 1530008. http://dx.doi.org/10.1142/s0218301315300088.

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In this review, I present the description of the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework, from the pre-collision high energy nuclear wave function to the point where hydrodynamics may start becoming applicable.

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Larzul, Ancel, and Marco Schiró. "Quenches and (pre)thermalization in a mixed Sachdev-Ye-Kitaev model." Physical Review B 105, no. 4 (January 3, 2022). http://dx.doi.org/10.1103/physrevb.105.045105.

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Mukaida, Kyohei, and Masaki Yamada. "Cascades of high-energy SM particles in the primordial thermal plasma." Journal of High Energy Physics 2022, no. 10 (October 18, 2022). http://dx.doi.org/10.1007/jhep10(2022)116.

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Abstract High-energy standard model (SM) particles in the early Universe are generated by the decay of heavy long-lived particles. The subsequent thermalization occurs through the splitting of high-energy primary particles into lower-energy daughters in primordial thermal plasma. The principal example of such processes is reheating after inflation caused by the decay of inflatons into SM particles. Understanding of the thermalization at reheating is extremely important as it reveals the origin of the hot Universe, and could open up new mechanisms for generating dark matter and/or baryon asymmetry. In this paper, we investigate the thermalization of high-energy SM particles in thermal plasma, taking into account the Landau-Pomeranchuk-Migdal effect in the leading-log approximation. The whole SM particle content and all the relevant SM interactions are included for the first time, i.e., the full gauge interactions of SU(3)c×SU(2)L×U(1)Y and the top Yukawa interaction. The distribution function of each SM species is computed both numerically and analytically. We have analytically obtained the distribution function of each SM species after the first few splittings. Furthermore, we demonstrate that, after a sufficient number of splittings, the particle distributions are asymptotic to certain values at low momentum, independent of the high-energy particles injected by inflaton decay. The results are useful to calculate the DM abundance produced during the pre-thermal phase. An example is provided to illustrate a way to calculate the DM abundance from the scattering between the thermal plasma and high-energy particles in the cascade.

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Nebel, C. E., H. C. Weller, and G. H. Bauer. "Hopping of Electrons in Hybrid Band Tails of a-Si1-xGex:H." MRS Proceedings 192 (1990). http://dx.doi.org/10.1557/proc-192-151.

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ABSTRACTThe thermalization of electrons in the medium temperature range (120K ≤ T ≤ 200K) is investigated by time-of-flight experiments on a-SiGe:H mim structures. The evaluation of the pre-transit current decay reveals a dual slope characteristic which reflects an initial hopping down (I ∼ t−1) followed by a thermally activated (I ∼ t−p 0 < p < 1) process. The transition time from hopping down to multiple trapping sensitively depends on temperature and alloy composition. The experimentally deduced features can be explained by the increased tail state density at the conduction band mobility edge of a-SiGe:H samples compared to a-Si:H.

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14

El Bourakadi, K., M. Ferricha-Alami, H. Filali, Z. Sakhi, and M. Bennai. "Gravitational waves from preheating in Gauss–Bonnet inflation." European Physical Journal C 81, no. 12 (December 2021). http://dx.doi.org/10.1140/epjc/s10052-021-09946-4.

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AbstractWe study gravitational wave production in an expanding Universe during the first stages following inflation, and investigate the consequences of the Gauss–Bonnet term on the inflationary parameters for a power-law inflation model with a GB coupling term. Moreover, we perform the analyses on the preheating parameters involving the number of e-folds $$N_{pre}$$ N pre , and the temperature of thermalization $$T_{th},$$ T th , and show that it’s sensitive to the parameters n, and $$\gamma $$ γ , the parameter $$\gamma $$ γ is proposed to connect the density energy at the end of inflation to the preheating energy density. We set a correlation of gravitational wave energy density spectrum with the spectral index $$n_{s}$$ n s detected by the cosmic microwave background experiments. The density spectrum $$\varOmega _{gw}$$ Ω gw shows good consistency with observation for $$\gamma =$$ γ = $$10^{3}$$ 10 3 and $$10^{6}$$ 10 6 . Our findings suggest that the generation of gravitational waves (GWs) during preheating can satisfy the constraints from Planck’s data.

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15

Sundström, Andréas, Laurent Gremillet, Evangelos Siminos, and István Pusztai. "Fast collisional electron heating and relaxation in thin foils driven by a circularly polarized ultraintense short-pulse laser." Journal of Plasma Physics 86, no. 2 (April 2020). http://dx.doi.org/10.1017/s0022377820000264.

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The creation of well-thermalized, hot and dense plasmas is attractive for warm dense matter studies. We investigate collisionally induced energy absorption of an ultraintense and ultrashort laser pulse in a solid copper target using particle-in-cell simulations. We find that, upon irradiation by a $2\times 10^{20}~\text{W}\,\text{cm}^{-2}$ intensity, 60 fs duration, circularly polarized laser pulse, the electrons in the collisional simulation rapidly reach a well-thermalized distribution with ${\sim}3.5~\text{keV}$ temperature, while in the collisionless simulation the absorption is several orders of magnitude weaker. Circular polarization inhibits the generation of suprathermal electrons, while ensuring efficient bulk heating through inverse bremsstrahlung, a mechanism usually overlooked at relativistic laser intensity. An additional simulation, taking account of both collisional and field ionization, yields similar results: the bulk electrons are heated to ${\sim}2.5~\text{keV}$ , but with a somewhat lower degree of thermalization than in the pre-set, fixed-ionization case. The collisional absorption mechanism is found to be robust against variations in the laser parameters. At fixed laser pulse energy, increasing the pulse duration rather than the intensity leads to a higher electron temperature.

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Song, Qufei, Long Zhu, and Jun Su. "Target dependence of isotopic cross sections in the spallation reactions $^{238}$U + p, d and $^{9}$Be at 1A GeV." Chinese Physics C, March 30, 2022. http://dx.doi.org/10.1088/1674-1137/ac6249.

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Abstract Background: The spallation of 238U is an important way to produce rare isotopes. Purpose: This work aims to study the cross sections of isotopes produced in 238U + p, d and 9Be reactions at 1A GeV and their target dependence. Methods: The isospin-dependent quantum molecular dynamics (IQMD) model is used to study the non-equilibrium thermalization of the 238U nuclei and the fragmentation of the hot system. The subsequent decay of the pre-fragments is simulated by the GEMINI++ model. The Bayesian neural network (BNN) algorithm is used to improve the prediction accuracy after learning the residual error between the experimental data and calculations by the IQMD-GEMINI++ model. Results: It is shown that the IQMD-GEMINI++ model can reproduce the available experimental data (3282 points) within 1.5 orders of magnitude. After being fine tuned by the BNN algorithm, the deviation between the calculations and experimental data were reduced to within 0.4 order of magnitude. Based on the predictions by the IQMD-GEMINI++-BNN framework, the cross sections to produce the rare isotopes by the 238U + p, d and 9Be reactions at 1A GeV are compared. For generation of neutron-rich fission products, the cross sections for the 238U + 9Be are the largest. For generation of neutron-deficient nuclei in the region of A = 200-220, the cross sections for 238U + p reaction are the largest. Conclusions: Considering the largest cross sections and the atomic density, the beryllium target is recommended to the produce the neutron-rich fission products by the 238U beam at 1A GeV, while the liquid-hydrogen target is suggested to the produce the neutron-deficient nuclei in the region of A = 200-220.

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Xiao, Erxi, Yujie Feng, Xin Lei, Long Zhu, and Jun Su. "Dissipation of energy and higher-order fluctuations of the largest fragment charge in the projectile fragmentation." Journal of Physics G: Nuclear and Particle Physics, January 26, 2022. http://dx.doi.org/10.1088/1361-6471/ac4f28.

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Abstract The higher-order fluctuations of the largest fragment charge were found to exhibit the signatures of a second-order phase transition in experimental data and simulations of the statistical multifragmentation model recently [PLB809(2020)135763]. This work is devoted to study the dissipation of energy and higher-order fluctuations of the largest fragment charge in the projectile fragmentation. The isospin-dependent quantum molecular dynamics (IQMD) model is used to study the non-equilibrium thermalization and fragmentation. The statistical code GEMINI is applied to simulate the second decay of the pre-fragments. To reveal how the incident energy dissipates into the excitation energy of the projectile-like system, the time evolution of the density, collective velocity, and random kinetic energy are displayed. It is found that the competition between the heat conduction and heat flux affects the excitation energy of projectile-like system, which is the key variable in the fragmenting process. Displaying the mean multiplicity of the intermediate mass fragments and the higher-order fluctuations of the largest fragment charge, it is found that the decay mechanism of the projectile-like system transfers from the multi-fragmentation at mid-peripheral collision into the nucleon-evaporation at peripheral collision. The pseudo-critical point of this transition can be indicated by the zero of third order fluctuation together with the minimum of fourth order fluctuation. The calculations of the pseudo-critical point by the IQMD+GEMINI model agree with that extracted from the experimental data. Finally, the influences of the pseudo-critical point by the second decay, the mass number of the colliding system, and the incident energy are studied.

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Journal articles on the topic 'Pre-Thermalization'

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