Other Condensed Matter
The dynamic structure factor of superfluid $^4$He has been investigated at very low temperatures by inelastic neutron scattering. The measurements combine different incoming energies resulting in an unprecedentedly large dynamic range with…
We report experimental realization of a quantum time quasicrystal, and its transformation to a quantum time crystal. We study Bose-Einstein condensation of magnons, associated with coherent spin precession, created in a flexible trap in…
In order to simplify the theoretical description of spasers, a gain medium is commonly represented by a two-level system. A realistic model, however, should have four levels. By using the Lindblad equations we develop a description of such…
We present a method for reconstructing the phonon relaxation time distribution $\tau_{\omega}= \tau (\omega)$ (including polarization) in a material from thermal spectroscopy data. The distinguishing feature of this approach is that it does…
We show that the recently introduced iterative backflow renormalization can be interpreted as a general neural network in continuum space with non-linear functions in the hidden units. We use this wave function within Variational Monte…
We propose to study the transition from a nodal loop to nodal chain phase in a tunable two-dimensional $\pi$-flux lattice with periodical modulation potential. The Hamiltonian describes a periodically modulated optical lattice system under…
We demonstrate that the synchronization of a lattice of solid-state condensates when inter-site tunnelling is switched on, depends strongly on the weak local disorder. This finding is vital for implementation of condensate arrays as…
Nonlinear phononics play important role in strong laser-solid interactions. We discuss nonlinear dynamical protocols which allow for efficient excitation and control of nonlinear phonons. We consider recent inspiring proposals: inducing…
Ultrasonic wave attenuation({\alpha}) measurement by pulse-echo method exhibits pronounced dependence on experimental conditions. It is shown to be an inherent characteristic of the method itself. Estimation of {\alpha} from the component…
Asymmetric lineshapes are experimentally observed in Raman spectra of different classes of condensed matter. Determination of the peak parameters, typically done with symmetric pseudo-Voigt functions, in such situations yields unreliable…
The physical properties of the spinel LiGaCr4S8 have been studied with neutron diffraction, X-ray diffraction, magnetic susceptibility and heat capacity measurements. The neutron diffraction and synchrotron X-ray diffraction data reveal…
We discuss surface scattering in terms of bidirectional reflectance distribution function. We formulate a boundary condition that in addition to diffuse and specular reflection has tilted diffuse reflection. We apply the boundary condition…
From topology of the order parameter of the magnon condensate observed in yttrium-iron-garnet (YIG) magnetic films one must not expect energetic barriers making spin supercurrents metastable. But we show that some barriers of dynamical…
The discovery of graphene and the related fascinating capabilities have triggered an unprecedented interest in inorganic two-dimensional (2D) materials. Despite the impressive impact in a variety of photonic applications, the absence of…
Spin-lattice relaxation of the nuclear spin system in p-type GaAs is studied using a three-stage experimental protocol including optical pumping and measuring the difference of the nuclear spin polarization before and after a dark interval…
The Bohr-Sommerfeld quantization rule lies at the heart of the modern semiclassical theory of a Bloch electron in a magnetic field. This rule is predictive of Landau levels and quantum oscillations for conventional metals, as well as for a…
Ultrasnsitive multi-mode electron spin resonance spectroscopy in the $SrLaAlO_4$ dielectric resonator at $20~mK$ reveals ferromagnetic states of $Mn^{4+}$ impurity ion. The formation of ferromagnetic states in the $MnO_6$ complex implies to…
The coupled dynamics of the two-fluid model of superfluid $^4$He is numerically studied for quantum turbulence of the thermal counterflow in a square channel. We combine the vortex filament model of the superfluid and the Navier-Stokes…
The problem of quantum turbulence in a channel with an inhomogeneous counterflow of superfluid turbulent helium is studied. \ The counterflow velocity $V_{ns}^{x}(y)$ along the channel is supposed to have a parabolic profile in the…
We report a theoretical study of the second harmonic generation in a noncollinearly magnetized conductive medium with equilibrium spin current. The hydrodynamic model is used to unravel the mechanism of a novel effect of the double…