arXiv subjects

Alexey Ermakov

Publications and source records attributed to Alexey Ermakov.

6 recordsLinked to original sources

arXiv2026

Valley-Controlled Viscosity of Two-Dimensional Dirac Fluids

Motivated by recent experiments in weakly hybridized small-angle twisted bilayer graphene, we investigate how valley imbalance affects the viscosity of two-dimensional Dirac fluids. We show that shifting the two low-energy Dirac cones relative to one another provides a direct knob to control the viscosity of the electron fluid. As the splitting is increased, the system passes through distinct transport regimes associated with valley depletion, charge-neutrality crossover, and the onset of electron-hole scattering, producing a pronounced nonmonotonic response. To place this result in context, we also analyze the viscosity in monolayer graphene (MLG) and two-dimensional electron gas (2DEG). We show that, due to the strong dependence of its inertial mass density on temperature, the kinematic viscosity of MLG is a monotonically decreasing function of temperature. Our results identify valley control as a route to tuning hydrodynamic transport in Dirac materials and clarify the interplay between band structure, scattering phase space, and screening in setting the viscous response.

cond-mat.mes-hall↗

arXiv2026

Non-Fermi-liquid behaviour of electrons coupled to gauge phonons

We identify overdamped gauge phonons as a new microscopic route to non-Fermi-liquid behaviour in Dirac materials. These phonons couple to electronic currents rather than densities, thereby realising a lattice analogue of transverse gauge-field mechanisms without requiring proximity to a quantum critical point. By computing the electronic self-energy with a phonon propagator dressed by electron-phonon interactions, we show that the low-energy behaviour is controlled by the orbital susceptibility chi and a dimensionless damping parameter alpha. In the overdamped regime, alpha >> 1, quasiparticles display strong deviations from Fermi-liquid theory. For chi > 0, Fermi-liquid behaviour persists only in a parametrically narrow infrared window before crossing over to non-Fermi-liquid scaling. For chi < 0, the Fermi-liquid regime is replaced by marginal-Fermi-liquid behaviour at the lowest energies, followed by a crossover to non-Fermi-liquid scaling. These results establish strain-induced gauge phonons as a promising source of anomalous metallic behaviour in systems such as twisted bilayer graphene.

cond-mat.str-el↗

arXiv2025

Spin and Charge Transport Mediated by Fractionalized Excitations

We study charge and spin transport in systems composed of itinerant electrons and localized magnetic moments of a Kitaev quantum spin liquid (QSL) phase. For example, $\alpha-{\rm RuCl}_3$ either intrinsically doped or in proximity to graphene. Our analysis reveals distinct temperature-dependent transport behaviors due to the QSL gap and the Majorana excitation spectrum, which are greatly enhanced when the velocities of itinerant-electrons and QSL excitations become comparable. These transport characteristics could potentially be employed to reveal the fractionalized excitations of the spin liquid.

cond-mat.mes-hall↗

arXiv2022

Holographic model for light quarks in anisotropic hot dense QGP with external magnetic field

We present a five-dimensional twice anisotropic holographic model supported by Einstein-dilaton-three-Maxwell action describing light quarks. The first of the Maxwell fields provides finite chemical potential. The second Maxwell field serves for anisotropy, characterizing spatial anisotropy of the QGP produced in heavy-ion collisions (HIC). The third Maxwell field is related to a magnetic field that appears in HIC. The dependence of the 5-dim black hole solution and confinement/deconfinement phase diagram on this magnetic field is considered. The effect of the inverse magnetic catalyses for light quarks phase diagram is obtained. Positions of critical end points are found. We also study the behavior of the conductivity for light quarks in both isotropic and anisotropic cases and show that behaviour of the conductivity near critical points essentially depend on quark masses, meanwhile at high temperature they are similar.

hep-th↗

arXiv2022

Direct photons emission rate and electric conductivity in twice anisotropic QGP holographic model with first-order phase transition

The electric conductivity and direct photons emission rate are considered in the holographic theory with two types of anisotropy. The electric conductivity is derived in two different ways, and their equivalence for the twice anisotropic theory is shown. Numerical calculations of the electric conductivity were done for Einstein-dilaton-three-Maxwell holographic model [29]. The dependence of the conductivity on the temperature, the chemical potential, the external magnetic field, and the spatial anisotropy of the heavy-ions collision (HIC) is studied. The electric conductivity jumps near the first-order phase transition are observed. This effect is similar to the jumps of holographic entanglement that were studied previously.

hep-th↗

arXiv2017

Testing Docker Performance for HPC Applications

The main goal for this article is to compare performance penalties when using KVM virtualization and Docker containers for creating isolated environments for HPC applications. The article provides both data obtained using commonly accepted synthetic tests (High Performance Linpack) and real life applications (OpenFOAM). The article highlights the influence on resulting application performance of major infrastructure configuration options: CPU type presented to VM, networking connection type used.

cs.PF↗