Nuclear Theory·nucl-th

Tuesday·October 3, 2017

25 papers—15 primary·10 cross-listed

16
[Submitted on 6 Jul 2017] (cross-list from cond-mat.supr-con)
A Two-band Model for p-wave Superconductivity
Heron Caldas · F. S. Batista · Mucio A. Continentino · Fernanda Deus · David Nozadze
In this paper we study the effects of hybridization in the superconducting properties of a two-band system. We consider the cases that these bands are formed by electronic orbitals with angular momentum, such that, the hybridization $V (k)$ among them can be symmetric or antisymmetric under inversion symmetry. We take into account only intra-band attractive interactions in the two bands and investigate the appearance of an induced inter-band pairing gap. We show that (inter-band) superconducting orderings are induced in the total absence of attractive interaction between the two bands, which turns out to be completely dependent on the hybridization between them. For the case of antisymmetric hybridization we show that the induced inter-band superconductivity has a p-wave symmetry.
Comments:
Published version
Subjects:
Superconductivity (cond-mat.supr-con); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
arXiv:
1707.01977 [pdf]
Annals Phys.(2017)·3 citations
17
[Submitted on 29 Sept 2017] (cross-list from astro-ph.HE)
Superfluidity and Superconductivity in Neutron Stars
Brynmor Haskell · Armen Sedrakian
This review focuses on applications of the ideas of superfluidity and superconductivity in neutron stars in a broader context, ranging from the microphysics of pairing in nucleonic superfluids to macroscopic manifestations of superfluidity in pulsars. The exposition of the basics of pairing, vorticity and mutual friction can serve as an introduction to the subject. We also review some topics of recent interest, including the various types of pinning of vortices, glitches, and oscillations in neutron stars containing superfluid phases of baryonic matter.
Comments:
Review commissioned for publication in the White Book of "NewCompStar" European COST Action MP1304
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1709.10340 [pdf]
Astrophys.Space Sci.Libr.(2018)·89 citations
18
[Submitted on 29 Sept 2017] (cross-list from hep-ph)
Factorization and Resummation for Groomed Multi-Prong Jet Shapes
Andrew J. Larkoski🇺🇸 · Ian Moult🇺🇸 · Duff Neill🇺🇸
Observables which distinguish boosted topologies from QCD jets are playing an increasingly important role at the Large Hadron Collider (LHC). These observables are often used in conjunction with jet grooming algorithms, which reduce contamination from both theoretical and experimental sources. In this paper we derive factorization formulae for groomed multi-prong substructure observables, focusing in particular on the groomed $D_{2}$ observable, which is used to identify boosted hadronic decays of electroweak bosons at the LHC. Our factorization formulae allow systematically improvable calculations of the perturbative $D_{2}$ distribution and the resummation of logarithmically enhanced terms in all regions of phase space using renormalization group evolution. They include a novel factorization for the production of a soft subjet in the presence of a grooming algorithm, in which clustering effects enter directly into the hard matching. We use these factorization formulae to draw robust conclusions of experimental relevance regarding the universality of the $D_{2}$ distribution in both $e^{+} e^{-}$ and $pp$ collisions. In particular, we show that the only process dependence is carried by the relative quark vs. gluon jet fraction in the sample, no non-global logarithms from event-wide correlations are present in the distribution, hadronization corrections are controlled by the perturbative mass of the jet, and all global color correlations are completely removed by grooming, making groomed $D_{2}$ a theoretically clean QCD observable even in the LHC environment. We compute all ingredients to one-loop accuracy, and present numerical results at next-to-leading logarithmic accuracy for $e^{+} e^{-}$ collisions, comparing with parton shower Monte Carlo simulations. Results for $pp$ collisions, as relevant for phenomenology at the LHC, are presented in a companion paper.
Comments:
66 pages, 18 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1710.00014 [pdf]
JHEP(2018)·50 citations
19
[Submitted on 30 Sept 2017] (cross-list from gr-qc)
Hot Spaghetti: Viscous Gravitational Collapse
Berndt Müller🇺🇸 · Andreas Schäfer🇩🇪
We explore the fate of matter falling into a macroscopic Schwarzschild black hole for the simplified case of a radially collapsing thin spherical shell for which the back reaction of the geometry can be neglected. We treat the internal dynamics of the infalling matter in the framework of viscous relativistic hydrodynamics and calculate how the internal temperature of the collapsing matter evolves as it falls toward the Schwarzschild singularity. We find that viscous hydrodynamics fails when either, the dissipative radial pressure exceeds the thermal pressure and the total radial pressure becomes negative, or the time scale of variation of the tidal forces acting on the collapsing matter becomes shorter than the characteristic hydrodynamic response time.
Comments:
Invited talk presented at the FIAS International Symposion on Discoveries at the Frontiers of Science - Dedicated to the memory of Walter Greiner
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1710.00136 [pdf]
EPJA(2018)·0 citations
20
[Submitted on 1 Oct 2017] (cross-list from hep-th)
Nonlinear Responses of Chiral Fluids from Kinetic Theory
Yoshimasa Hidaka🇯🇵 · Shi Pu🇯🇵 · Di-Lun Yang🇯🇵
The second-order nonlinear responses of inviscid chiral fluids near local equilibrium are investigated by applying the chiral kinetic theory (CKT) incorporating side-jump effects. It is shown that the local equilibrium distribution function can be non-trivially introduced in a co-moving frame with respect to the fluid velocity when the quantum corrections in collisions are involved. For the study of anomalous transport, contributions from both quantum corrections in anomalous hydrodynamic equations of motion and those from the CKT and Wigner functions are considered under the relaxation-time (RT) approximation, which result in anomalous charge Hall currents propagating along the cross product of the background electric field and the temperature (or chemical-potential) gradient and of the temperature and chemical-potential gradients. On the other hand, the nonlinear quantum correction on the charge density vanishes in the classical RT approximation, which in fact satisfies the matching condition given by the anomalous equation obtained from the CKT.
Comments:
34 pages, a missing term of collisions in Eq.(8) and relevant parts added, results and conclusions remain unchanged
Subjects:
High Energy Physics — Theory (hep-th); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
1710.00278 [pdf]
PRD(2018)·165 citations
21
[Submitted on 1 Oct 2017] (cross-list from hep-ph)
Cumulant Expansion in Gluon Saturation, and Five and Six-Gluon Azimuthal Correlations
Sener Ozonder🇹🇷
Correlations between the momenta of the final state hadrons measured in proton or nucleus collisions contain information that sheds light on the initial conditions and evolutionary dynamics of the collision system. These correlation measurements have revealed the long-range rapidity correlations in p-p and p-Pb systems, and they have also made it possible to extract the elliptic flow coefficient from hadron correlation measurements. In this work, we calculate five- and six-gluon correlation functions in the framework of saturation physics by using superdiagrams. We also derive the cumulant expansion of the gluon correlators that is valid in the gluon saturation limit. We show that the cumulant expansion of the gluon correlators that is used for counting the number of diagrams to be calculated does not follow the standard cumulant expansion. We also explain how these findings can be used in obtaining experimentally relevant observables such as flow coefficients calculated from correlations as well as ratios of the correlation functions of different orders.
Comments:
13 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1710.00425 [pdf]
PRD(2017)·3 citations
22
[Submitted on 2 Oct 2017] (cross-list from hep-lat)
Baryons in the plasma: in-medium effects and parity doubling
Gert Aarts🇬🇧 · Chris Allton🇬🇧 · Davide de Boni🇬🇧 · Simon Hands🇬🇧 · Benjamin Jäger🇨🇭 · Chrisanthi Praki🇬🇧 · Jon-Ivar Skullerud🇮🇪
We investigate the fate of baryons made out of u, d and s quarks in the hadronic gas and the quark-gluon plasma, using nonperturbative lattice simulations, employing the FASTSUM anisotropic Nf=2+1 ensembles. In the confined phase a strong temperature dependence is seen in the masses of the negative-parity groundstates, while the positive-parity groundstate masses are approximately temperature independent, within the error. At high temperature parity doubling emerges. A noticeable effect of the heavier s quark is seen. We give a simple description of the medium-dependent masses for the negative-parity states and speculate on the relevance for heavy-ion phenomenology via the hadron resonance gas.
Comments:
4 pages, presented at Strangeness in Quark Matter, Utrecht, the Netherlands, 10-15 July 2017
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1710.00566 [pdf]
EPJ Web Conf.(2018)·16 citations
23
[Submitted on 19 Sept 2017] (cross-list from cond-mat.str-el)
Functional Renormalization Group and Kohn-Sham scheme in Density Functional Theory
Haozhao Liang🇯🇵 · Yifei Niu🇷🇴 · Tetsuo Hatsuda🇯🇵
Deriving accurate energy density functional is one of the central problems in condensed matter physics, nuclear physics, and quantum chemistry. We propose a novel method to deduce the energy density functional by combining the idea of the functional renormalization group and the Kohn-Sham scheme in density functional theory. The key idea is to solve the renormalization group flow for the effective action decomposed into the mean-field part and the correlation part. Also, we propose a simple practical method to quantify the uncertainty associated with the truncation of the correlation part. By taking the $φ^{4}$ theory in zero dimension as a benchmark, we demonstrate that our method shows extremely fast convergence to the exact result even for the highly strong coupling regime.
Comments:
6 pages, 3 figures, and 1 table
Subjects:
Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
1710.00650 [pdf]
PLB(2018)·33 citations
24
[Submitted on 2 Oct 2017] (cross-list from hep-ph)
Elliptic flow coefficients from transverse momentum conservation
Adam Bzdak🇵🇱 · Guo-Liang Ma🇨🇳
We calculate the $k$ -particle ( $k = 2, 4, 6, 8$ ) azimuthal cumulants resulting from the conservation of transverse momentum. We find that $c_{2} {k} > 0$ and depending on the transverse momenta, $c_{2} {k}$ can reach substantial values even for a relatively large number of particles. The impact of our results on the understanding of the onset of collectivity in small systems is emphasized.
Comments:
8 pages, 1 figure; PRC version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1710.00653 [pdf]
PRC(2018)·11 citations
25
[Submitted on 2 Oct 2017] (cross-list from hep-ph)
Baryon-antibaryon annihilation and reproduction in relativistic heavy-ion collisions
E. Seifert🇩🇪 · W. Cassing🇩🇪
The quark rearrangement model for baryon-antibaryon annihilation and reproduction ( $B B ˉ \leftrightarrow 3 M$ ) - incorporated in the Parton-Hadron-String Dynamics (PHSD) transport approach - is extended to the strangeness sector. A derivation of the transition probabilities for the three-body processes is presented and a strangeness suppression factor for the invariant matrix element squared is introduced to account for the higher mass of the strange quark compared to the light up and down quarks. In simulations of the baryon-antibaryon annihilation and reformation in a box with periodic boundary conditions we demonstrate that our numerical implementation fulfills detailed balance on a channel-by-channel basis for more than 2000 individual $2 \leftrightarrow 3$ channels. Furthermore, we study central Pb+Pb collisions within PHSD from 11.7 $A$ GeV to 158 $A$ GeV and investigate the impact of the additionally implemented reaction channels in the strangeness sector. We find that the new reaction channels have a visible impact essentially only on the rapidity spectra of antibaryons. The spectra with the additional channels in the strangeness sector are closer to the experimental data than without for all antihyperons. Due to the chemical redistribution between baryons/antibaryons and mesons we find a slightly larger production of antiprotons thus moderately overestimating the available experimental data. We additionally address the question if the antibaryon spectra (with strangeness) from central heavy-ion reactions at these energies provide further information on the issue of chiral symmetry restoration and deconfinement. However, by comparing transport results with/without partonic phase as well as including/excluding effects from chiral symmetry restoration we find no convincing signals in the strange antibaryon sector for either transition due to the strong final-state interactions.
Comments:
19 pages, 19 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1710.00665 [pdf]
PRC(2018)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE