Related papers: Rotational superradiance with Bogoliubov dispersio…
Rotational superradiance was predicted theoretically decades ago, and is chiefly responsible for a number of important effects and phenomenology in black-hole physics. However, rotational superradiance has never been observed…
Motivated by analogue models of classical and quantum field theory in curved spacetimes and their recent experimental realizations, we consider wave scattering processes of dispersive fields exhibiting two extra degrees of freedom. In…
Solitons propagating in media with higher order dispersion will shed radiation known as dispersive wave or resonant radiation, with applications in frequency broadening, deep UV sources for spectroscopy or simply fundamental studies of…
We analyze the consequences caused by a deformed dispersion relation, suggested in several quantum gravity models, upon a bosonic gas. Concerning the ground state of the Bogoliubov space of this system, we deduce the corrections in the…
Quasiparticle approach to dynamics of dark solitons is applied to the case of ring solitons. It is shown that the energy conservation law provides the effective equations of motion of ring dark solitons for general form of the nonlinear…
The axisymmetric acoustic perturbations in the velocity potential of a Bose-Einstein condensate in the presence of a single vortex behave like minimally coupled massless scalar fields propagating in a curved (1+1) dimensional Lorentzian…
The amplification of radiation by superradiance is a universal phenomenon observed in numerous physical systems. We demonstrate that superradiant scattering generates entanglement for different input states, including coherent states,…
We study theoretically the collective dynamics of rotational excitations of polar molecules loaded into an optical lattice in two dimensions. These excitations behave as hard-core bosons with a relativistic energy dispersion arising from…
In the presence of massive bosonic degrees of freedom, rotational superradiance can trigger an instability that spins down black holes. This leads to peculiar gravitational-wave signatures and distribution in the spin-mass plane, which in…
Disorder plays a crucial role in spin dynamics in solids and condensed matter systems. We demonstrate that for a spin-orbit coupled Bose-Einstein condensate in a random potential two mechanisms of spin evolution, that can be characterized…
Wave scattering phenomena are ubiquitous to almost all Sciences, from Biology to Physics. When an incident wave scatters off of an obstacle, it is partially reflected and partially transmitted. Since the scatterer absorbs part of the…
Appearance of quantized vortices in a superfluid and a Bose-Einstein condensate (BEC) stems from their nontrivial response to broken time-reversal symmetry (TRS). Here we show that breaking of the TRS by, for example, rotation or an…
The classic Bogoliubov theory of weakly interacting Bose gases rests upon the assumption that nearly all the bosons condense into the lowest quantum state at sufficiently low temperatures. Here we develop a generalized version of Bogoliubov…
It is a common view that rotational motion in a superfluid can exist only in the presence of quantized vortices. However, in our numerical studies on the merging of two concentric Bose-Einstein condensates with axial symmetry in…
We present a kinetic description of superfluid currents in ring-shaped Bose-Einstein condensates based on the Wigner phase-space formalism. Starting from the Gross-Pitaevskii equation in a toroidal geometry, we derive a Vlasov-type equation…
We theoretically study harmonically trapped one-dimensional Bose gases (e.g., Li, Na, K, Rb, etc.) with multibands occupied, focusing on effects of higher-energy bands. Combining the Ginzburg-Landau theory with the bosonization techniques,…
It is a well-known fact that compact gravitating objects admit bound state configurations for massive bosonic fields. In this work we describe a new class of superradiant instabilities of axion bound states in neutron star magnetospheres.…
In this paper we consider two models which exhibit equilibrium BEC superradiance. They are related to two different types of superradiant scattering observed in recent experiments. The first one corresponds to the amplification of…
The ground state of a rotating Bose-Einstein condensate trapped in a two-dimensional anharmonic--anisotropic potential is analyzed numerically at the limit of an infinite number of particles. We find that the density breaks up along the $x$…
The one-body density matrix of weakly interacting, condensed bosons in external potentials is calculated using inhomogeneous Bogoliubov theory. We determine the condensate deformation caused by weak external potentials on the mean-field…