arXiv subjects

L. A. Melnikovsky

Publications and source records attributed to L. A. Melnikovsky.

13 recordsLinked to original sources

arXiv2026

Superconducting Triple Point in UTe$_2$: Thermodynamics and Symmetry

Three lines of second-order phase transitions between the normal phase and two distinct superconducting phases meet at a single point on the phase diagram of UTe$_2$. Although it is commonly believed otherwise, such triple points are not subject to thermodynamic constraints. The phase diagram is interpreted within Landau theory in terms of two superconducting order parameters with different gauge symmetries. Such an interpretation is unique under the assumption of spatial uniformity.

cond-mat.supr-con↗

arXiv2024

Vortices in Andreev-Bashkin Superfluids

Andreev-Bashkin entrainment makes the hydrodynamics of the binary superfluid solution particularly interesting. We investigate stability and motion of quantum vortices in such system.

cond-mat.other↗

arXiv2023

Overcritical Fermi Superfluids

Superfluidity in Fermi systems is not destroyed by a flow exceeding the Landau velocity threshold. The overcritical state acquires normal component even at zero temperature. We explore peculiar hydrodynamics of this system and discover two sound modes, for which the explicit universal dispersion relations are provided.

cond-mat.other↗

arXiv2020

Spin diffusion in liquid $^3$He confined in planar aerogel

We report the results of theoretical and experimental investigation of spin diffusion in the normal phase of liquid $^3$He confined in planar aerogel: a material consisting of nanostrands which are almost parallel to a specific plane and randomly oriented in this plane. Using spin echo technique we measure the spin diffusion coefficients in the directions perpendicular and parallel to the plane. We see good agreement between the experiment and the theory.

cond-mat.other↗

arXiv2015

Spin diffusion in liquid 3He confined in nafen

We report results of spin diffusion measurements in normal phase of liquid 3He confined in nafen. Nafen is a new type of aerogel and it consists of Al2O3 strands which are nearly parallel to one another at macroscopic distances. We examine two samples of nafen with different porosities using spin echo techniques. Spin diffusion of 3He along and across the strands was measured. The aerogel alignment is clearly evident from observed spin diffusion anisotropy. A theory describing this effect is developed and compared with the experiment.

cond-mat.supr-con↗

arXiv2012

Roton Parametric Resonance

Parametric excitation of rotons by oscillating electric field exhibits a narrow resonance at the roton minimum frequency. The resonance width is in good agreement with experimental results on the microwave absorption in superfluid helium.

cond-mat.other↗

arXiv2008

Quadrupole Stark Effect in Superfluid

The roton energy depends on applied electric field gradient due to its quadrupole moment. This may explain absorption line splitting recently observed experimentally.

cond-mat.other↗

arXiv2007

On Sound Reflection in Superfluid

We consider reflection of the first and the second sound waves by a rigid flat wall in superfluid. Nontrivial dependence of the reflection coefficients on the angle of incidence is obtained. Sound conversion is predicted at slanted incidence.

cond-mat.supr-con↗

arXiv2006

Polarization of Dielectrics by Acceleration

We argue that acceleration induces electric polarization in usual dielectrics. Both accelerations in superfluid participate in the medium polarization. Excitations contribution to the polarization is calculated at low temperatures. Estimates of the effect show order of magnitude agreement with recent experimental results on electric effect of superflow.

cond-mat.soft↗

arXiv2004

Heat Transfer in Superfluids: Effect of Gravity

We discuss the influence of an external field on energy transport in superfluid. He-II is not isothermal in presence of Earth gravity; instead, it supports finite temperature gradient given by a Fourier-like equation. We calculate asymptotic behavior of the effective heat resistance in the vicinity of the $λ$-transition.

cond-mat.soft↗

arXiv2004

Thermodynamics of Superfluidity

New, superfluid specific additive integral of motion is found. This facilitates investigation of general thermodynamic equilibrium conditions for superfluid. The analysis is performed in an extended space of thermodynamic variables containing (along with the usual thermodynamic coordinates such as pressure and temperature) superfluid velocity and momentum density. The equilibrium stability conditions lead to thermodynamic inequalities which replace the Landau superfluidity criterion at finite temperatures.

cond-mat.soft↗

arXiv2003

Thermodynamic inequalities in superfluid

We investigate general thermodynamic stability conditions for the superfluid. This analysis is performed in an extended space of thermodynamic variables containing (along with the usual thermodynamic coordinates such as pressure and temperature) superfluid velocity and momentum density. The stability conditions lead to thermodynamic inequalities which replace the Landau superfluidity criterion at finite temperatures.

cond-mat.stat-mech↗

arXiv2002

Two-velocity elasticity theory and facet growth

We explain the linear growth of smooth solid helium facets by the presence of lattice point defects. To implement this task, the framework of very general two-velocity elasticity theory equations is developed. Boundary conditions for these equations for various surface types are derived. We also suggest additional experiments to justify the concept.

cond-mat.stat-mech↗