arXiv subjects

Maxim N. Chernodub

Publications and source records attributed to Maxim N. Chernodub.

33 records · Page 2Linked to original sources

arXiv2023

Moment of inertia and supervortical temperature of gluon plasma

Using lattice simulations, we analyze the influence of uniform rotation on the equation of state of gluodynamics. For a sufficiently slow rotation, the free energy of the system can be expanded into a series of powers of angular velocity. We calculate the moment of inertia given by the quadratic coefficient of this expansion using both analytic continuation and derivative methods, which demonstrate a good agreement between the results. We find that the moment of inertia unexpectedly takes a negative value below the ``supervortical temperature'' $T_s = 1.50(10) T_c$, vanishes at $T = T_s$, and becomes a positive quantity at higher temperatures. We discuss how our results are related to the scale anomaly and the magnetic gluon condensate. We point out that the negativity of the moment of inertia is in qualitative agreement with our previous lattice calculations, indicating that the rigid rotation increases the critical temperatures in gluodynamics and QCD.

hep-lat↗

arXiv2023

Rigidly-rotating scalar fields: between real divergence and imaginary fractalization

The thermodynamics of rigidly rotating systems experience divergences when the system dimensions transverse to the rotation axis exceed the critical size imposed by the causality constraint. The rotation with imaginary angular frequency, suitable for numerical lattice simulations in Euclidean imaginary-time formalism, experiences fractalization of thermodynamics in the thermodynamic limit, when the system's pressure becomes a fractal function of the rotation frequency. Our work connects two phenomena by studying how thermodynamics fractalizes as the system size grows. We examine an analytically-accessible system of rotating massless scalar matter on a one-dimensional ring and the numerically treatable case of rotation in the cylindrical geometry and show how the ninionic deformation of statistics emerges in these systems. We discuss a no-go theorem on analytical continuation between real- and imaginary-rotating theories. Finally, we compute the moment of inertia and shape deformation coefficients caused by the rotation of the relativistic bosonic gas.

hep-th↗

arXiv2023

Helical Separation Effect and helical heat transport for Dirac fermions

An ensemble of massless fermions can be characterized by its total helicity charge given by the sum of axial charges of particles minus the sum of axial charges of antiparticles. We show that charged massless fermions develop a dissipationless flow of helicity along the background magnetic field. We dub this transport phenomenon as the Helical Separation Effect (HSE). Contrary to its chiral cousin, the Chiral Separation Effect, the HSE produces the helical current in a neutral plasma in which all chemical potentials vanish. In addition, we uncover the Helical Magnetic Heat Effect which generates a heat flux of Dirac fermions along the magnetic field in the presence of non-vanishing helical charge density. We also discuss possible hydrodynamic modes associated with the HSE in neutral plasma.

hep-th↗

arXiv2023

Preturbulence in momentum-relaxing Navier-Stokes hydrodynamics

In a hydrodynamic regime of electronic fluids, the electron scattering on impurities and phonons inhibits the development of oscillating preturbulent phenomena (such as the Kármán vortex shedding) and enforces a laminar flow. Working in a local generalization of the Navier-Stokes hydrodynamics of incompressible two-dimensional fluids, we show that the critical relaxation time separating these two regimes is described by a surprisingly simple fractional power function of the Reynolds number. The critical exponent, $α\simeq 4/3$, sets particular experimental conditions for the observation of preturbulent effects in electronic fluids.

physics.flu-dyn↗

arXiv2023

Boundary states and Non-Abelian Casimir effect in lattice Yang-Mills theory

Using first-principle numerical simulations, we investigate the Casimir effect in zero-temperature SU(3) lattice gauge theory in 3+1 spacetime dimensions. The Casimir interaction between perfect chromometallic mirrors reveals the presence of a new gluonic state with the mass $m_{\mathrm{gt}} = 1.0(1)\sqrtσ = 0.49(5)\,\mathrm{GeV} = 0.29(3) M_{0^{++}}$ which is substantially lighter than the $0^{++}$ groundstate glueball. We call this excitation ``glueton'' interpreting it as a non-perturbative colorless state of gluons bound to their negatively colored images in the chromometallic mirror. The glueton is a gluonic counterpart of a surface electron-hole exciton in semiconductors. We also show that a heavy quark is attracted to the neutral chromometallic mirror, thus supporting the existence of a ``quarkiton'' (a ``quark exciton'') colorless state in QCD, which is formed by a single quark with its anti-quark image in the chromometallic mirror. Analogies with edge modes in topological insulators and boundary states of fractional vortices in multi-component condensates are highlighted.

hep-lat↗

arXiv2022

IR/UV mixing from local similarity maps of scalar non-Hermitian field theories

We propose to "gauge" the group of similarity transformations that acts on a space of non-Hermitian scalar theories. We introduce the "similarity gauge field", which acts as a gauge connection on the space of non-Hermitian theories characterized by (and equivalent to a Hermitian) real-valued mass spectrum. This extension leads to new effects: if the mass matrix is not the same in distant regions of space, but its eigenvalues coincide pairwise in both regions, the particle masses stay constant in the whole spacetime, making the model indistinguishable from a standard, low-energy and scalar Hermitian one. However, contrary to the Hermitian case, the high-energy scalar particles become unstable at a particular wavelength determined by the strength of the emergent similarity gauge field. This instability corresponds to momentum-dependent exceptional points, whose locations cannot be identified from an analysis of the eigenvalues of the coordinate-dependent squared mass matrix in isolation, as one might naively have expected. For a doublet of scalar particles with masses of the order of 1 MeV and a similarity gauge rotation of order unity at distances of 1 meter, the corrections to the masses are about 10^{-7}eV, which makes no experimentally detectable imprint on the low-energy spectrum. However, the instability occurs at 10^{18} eV, suggestively in the energy range of detectable ultra-high-energy cosmic rays, thereby making this truly non-Hermitian effect and its generalizations of phenomenological interest for high-energy particle physics.

hep-th↗

arXiv2022

Pseudo-hydrodynamic flow of quasiparticles in semimetal WTe2 at room temperature

Recently, much interest has emerged in fluid-like electric charge transport in various solid-state systems. The hydrodynamic behavior of the electronic fluid reveals itself as a decrease of the electrical resistance with increasing temperature (the Gurzhi effect) in narrow conducting channels, polynomial scaling of the resistance as a function of the channel width, substantial violation of the Wiedemann-Franz law supported by the emergence of the Poiseuille flow. Similarly to whirlpools in flowing water, the viscous electronic flow generates vortices, resulting in abnormal sign-changing electrical response driven by the backflow of electrical current. Experimentally, the presence of the hydrodynamic vortices was observed in low-temperature graphene as a negative voltage drop near the current-injecting contacts. However, the question of whether the long-ranged sign-changing electrical response can be produced by a mechanism other than hydrodynamics has not been addressed so far. Here we use polarization-sensitive laser microscopy to demonstrate the emergence of visually similar abnormal sign-alternating patterns in charge density in multilayer tungsten ditelluride at room temperature where this material does not exhibit true electronic hydrodynamics. We argue that this pseudo-hydrodynamic behavior appears due to a subtle interplay between the diffusive transport of electrons and holes. In particular, the sign-alternating charge accumulation in WTe2 is supported by the unexpected backflow of compressible neutral electron-hole current, which creates charge-neutral whirlpools in the bulk of this nearly compensated semimetal. We demonstrate that the exceptionally large spatial size of the charge domains is sustained by the long recombination time of electron-hole pairs.

cond-mat.mes-hall↗

arXiv2021

Thermal transport, geometry, and anomalies

The relation between thermal transport and gravity was highlighted in the seminal work by Luttinger in 1964, and has been extensively developed to understand thermal transport, most notably the thermal Hall effect. Here we review the novel concepts that relate thermal transport, the geometry of space-time and quantum field theory anomalies. We give emphasis to the cross-pollination between emergent ideas in condensed matter, notably Weyl and Dirac semimetals, and the understanding of gravitational and scale anomalies stemming from high-energy physics. We finish by relating to recent experimental advances and presenting a perspective of several open problems.

cond-mat.mes-hall↗

arXiv2020

Vortices with magnetic field inversion in noncentrosymmetric superconductors

Superconducting materials with noncentrosymmetric lattices lacking space inversion symmetry exhibit a variety of interesting parity-breaking phenomena, including the magneto-electric effect, spin-polarized currents, helical states, and the unusual Josephson effect. We demonstrate, within a Ginzburg-Landau framework describing noncentrosymmetric superconductors with $O$ point group symmetry, that vortices can exhibit an inversion of the magnetic field at a certain distance from the vortex core. In stark contrast to conventional superconducting vortices, the magnetic-field reversal in the parity-broken superconductor leads to non-monotonic intervortex forces, and, as a consequence, to the exotic properties of the vortex matter such as the formation of vortex bound states, vortex clusters, and the appearance of metastable vortex/anti-vortex bound states.

cond-mat.supr-con↗

arXiv2020

Detect Axial Gauge Fields with a Calorimeter

Torsional strain in Weyl semimetals excites a unidirectional chiral density wave propagating in the direction of the torsional vector. This gapless excitation, named the chiral sound wave, is generated by a particular realization of the axial anomaly via the triple-axial (AAA) anomalous diagram. We show that the presence of the torsion-generated chiral sound leads to a linear behavior of the specific heat of a Weyl semimetal and to an enhancement of the thermal conductivty at experimentally accessible temperatures. We also demonstrate that such an elastic twist lowers the temperature of the sample, thus generating a new, anomalous type of elasto-calorific effect. Measurements of these thermodynamical effects will provide experimental verification of the exotic triple-axial anomaly as well as the reality of the elastic pseudomagnetic fields in Weyl semimetals.

cond-mat.mes-hall↗

arXiv2020

Topological susceptibility, divergent chiral density and phase diagram of chirally imbalanced QCD medium at finite temperature

We show that the nonlocal two-flavor Nambu--Jona-Lasinio model predicts the enhancement of both chiral and axial symmetry breaking as the chiral imbalance of hot QCD matter, regulated by a chiral chemical potential $μ_5$, increases. The two crossovers are reasonably close to each other in the range of $μ_5$ examined here and the pseudocritical temperatures rise with $μ_5$. The curvatures of the chiral and axial crossovers for the chiral quark chemical potential approximately coincide and give $κ_5 \simeq - 0.011$. We point out that the presence of $μ_5$ in thermodynamic equilibrium is inconsistent with the fact that the chiral charge is not a Noether-conserved quantity for massive fermions. The chiral chemical potential should not, therefore, be considered as a true chemical potential that sets a thermodynamically stable environment in the massive theory, but rather than as a new coupling that may require a renormalization in the ultraviolet domain. The divergence of an unrenormalized chiral density, \corr{coming from zero-point fermionic fluctuations,} is a consequence of this property. We propose a solution to this problem via a renormalization procedure.

hep-ph↗

arXiv2020

Non-Hermitian Chiral Magnetic Effect in Equilibrium

We analyze the Chiral Magnetic Effect for non-Hermitian fermionic systems using the biorthogonal formulation of quantum mechanics. In contrast to the Hermitian chiral counterparts, we show that the Chiral Magnetic Effect may take place in thermal equilibrium of an open non-Hermitian system with, generally, massive fermions. The key observation is that for non-Hermitian charged systems, there is no strict charge conservation as understood in the Hermitian case, so the Bloch theorem preventing currents in the thermodynamic limit in equilibrium does not apply.

cond-mat.mes-hall↗

arXiv2019

Fingerprints of the conformal anomaly on the thermoelectric transport in Dirac and Weyl semimetals: Result from a Kubo formula

In a recent work, a contribution to the Nernst current of a Dirac or Weyl semimetal coming from the conformal anomaly was reported. Being originated from an anomaly - a vacuum contribution -, a non-zero transport coefficient was predicted at zero temperature and chemical potential. In this work we perform a Kubo formula calculation of the thermoelectrical coefficient and confirm that the result agrees with the quantum field theory estimation in the limit of zero temperature and chemical potential. For finite chemical potential μ around μ = 0 the transverse Seebeck coefficient shows a plateau indicating that only the zero conformal Landau levels contributes to this intrinsic effect. This result opens the way to the experimental observation of a geometric anomaly which is much harder to explore than the standard chiral anomaly.

cond-mat.mes-hall↗

arXiv2014

A condensed matter realization of the axial magnetic effect

The axial magnetic effect, i.e., the generation of an energy current parallel to an axial magnetic field coupling with opposite signs to left- and right-handed fermions is a non-dissipative transport phenomenon intimately related to the gravitational contribution to the axial anomaly. An axial magnetic field emerges naturally in condensed matter in the so called Weyl semi-metals. We present a measurable implementation of the axial magnetic effect. We show that the edge states of a Weyl semimetal at finite temperature possess a temperature dependent angular momentum in the direction of the vector potential intrinsic to the system. Such a realization provides a plausible context for the experimental confirmation of the elusive gravitational anomaly.

hep-th↗

arXiv1999

Various Representations of Infrared Effective Lattice SU(2) Gluodynamics

We study various representations of infrared effective theory of SU(2) gluodynamics starting from the Abelian monopole action derived recently by numerical calculations in the Maximal Abelian projection. In particular we derive the string model and the dual Abelian-Higgs (dual Ginzburg-Landau) model which corresponds to infrared SU(2) gluodynamics. It occurs that the classical string tension in the string model is of the same order as the string tension in quantum SU(2) gluodynamics.

hep-lat↗