20 research outputs found
Optomechanical signature of a frictionless flow of superfluid light
We propose an experimental setup that should make it possible to reveal the
frictionless flow of a superfluid of light from the suppression of the drag
force that it exerts onto a material obstacle. In the paraxial-propagation
geometry considered here, the photon-fluid dynamics is described by a wave
equation analogous to the Gross-Pitaevskii equation of dilute Bose-Einstein
condensates and the obstacle consists in a solid dielectric slab immersed into
a nonlinear optical liquid. By means of an ab initio calculation of the
electromagnetic force experienced by the obstacle, we anticipate that
superfluidity is detectable in state-of-the-art experiments from the
disappearance of the optomechanical deformation of the obstacle.Comment: 10 pages, 4 figure
Hawking radiation in a two-component Bose-Einstein condensate
We consider a simple realization of an event horizon in the flow of a
one-dimensional two-component Bose-Einstein condensate. Such a condensate has
two types of quasiparticles; In the system we study, one corresponds to density
fluctuations and the other to polarization fluctuations. We treat the case
where a horizon occurs only for one type of quasiparticles (the polarization
ones). We study the one- and two-body signal associated to the analog of
spontaneous Hawking radiation and demonstrate by explicit computation that it
consists only in the emission of polarization waves. We discuss the
experimental consequences of the present results in the domain of atomic
Bose-Einstein condensates and also for the physics of exciton-polaritons in
semiconductor microcavities
Postquench prethermalization in a disordered quantum fluid of light
We study the coherence of a disordered and interacting quantum light field
after propagation along a nonlinear optical fiber. Disorder is generated by a
cross-phase modulation with a randomized auxiliary classical light field, while
interactions are induced by self-phase modulation. When penetrating the fiber
from free space, the incoming quantum light undergoes a disorder and
interaction quench. By calculating the coherence function of the transmitted
quantum light, we show that the decoherence induced by the quench spreads in a
light-cone fashion in the nonequilibrium many-body quantum system, leaving the
latter prethermalize with peculiar features originating from disorder.Comment: 18 pages, 5 figure
Wave pattern induced by a localized obstacle in the flow of a one-dimensional polariton condensate
Motivated by recent experiments on generation of wave patterns by a polariton
condensate incident on a localized obstacle, we study the characteristics of
such flows under the condition that irreversible processes play a crucial role
in the system. The dynamics of a non-resonantly pumped polariton condensate in
a quasi-one-dimensional quantum wire is modeled by a Gross-Pitaevskii equation
with additional phenomenological terms accounting for the dissipation and
pumping processes. The response of the condensate flow to an external potential
describing a localized obstacle is considered in the weak-perturbation limit
and also in the nonlinear regime. The transition from a viscous drag to a
regime of wave resistance is identified and studied in detail
Polarization hydrodynamics in a one-dimensional polariton condensate
We study the hydrodynamics of a nonresonantly-pumped polariton condensate in
a quasi-one-dimensional quantum wire taking into account the spin degree of
freedom. We clarify the relevance of the Landau criterion for superfluidity in
this dissipative two-component system. Two Cherenkov-like critical velocities
are identified corresponding to the opening of different channels of radiation:
one of (damped) density fluctuations and another of (weakly damped)
polarization fluctuations. We determine the drag force exerted onto an external
obstacle and propose experimentally measurable consequences of the specific
features of the fluctuations of polarization
Propagation of a quantum fluid of light in a cavityless nonlinear optical medium: General theory and response to quantum quenches
Making use of a generalized quantum theory of paraxial light propagation
where the radiation-axis and the temporal coordinates play exchanged roles, we
discuss the potential of bulk nonlinear optical media in cavityless
configurations for quantum statistical mechanics studies of the conservative
many-body dynamics of a gas of interacting photons. To illustrate the general
features of this point of view, we investigate the response of the fluid of
light to the quantum quenches in the photon-photon interaction constant
experienced at the front and the back faces of a finite slab of weakly
nonlinear material. Extending the standard Bogoliubov theory of dilute
Bose-Einstein condensates, peculiar features are predicted for the statistical
properties of the light emerging from the nonlinear medium.Comment: 17 pages, 4 figure
Nonlinear waves of polarization in two-component Bose-Einstein condensates
Waves with different symmetries exist in two-component Bose-Einstein
condensates (BECs) whose dynamics is described by a system of coupled
Gross-Pitaevskii (GP) equations. A first type of waves corresponds to
excitations for which the motion of both components is locally in phase. In the
second type of waves the two components have a counter-phase local motion. In
the case of different values of inter- and intra-component interaction
constants, the long wave-length behavior of these two modes corresponds to two
types of sound with different velocities. In the limit of weak nonlinearity and
small dispersion the first mode is described by the well-known Korteweg-de
Vries (KdV) equation. We show that in the same limit the second mode can be
described by the Gardner (modified KdV) equation, if the intra-component
interaction constants have close enough values. This leads to a rich
phenomenology of nonlinear excitations (solitons, kinks, algebraic solitons,
breathers) which does not exist in the KdV description.Comment: 10 pages, 5 figure
Pump-and-probe optical transmission phase shift as a quantitative probe of the Bogoliubov dispersion relation in a nonlinear channel waveguide
We theoretically investigate the dispersion relation of small-amplitude
optical waves superimposing upon a beam of polarized monochromatic light
propagating along a single-mode channel waveguide characterized by an
instantaneous and spatially local Kerr nonlinearity. These small luminous
fluctuations propagate along the waveguide as Bogoliubov elementary excitations
on top of a one-dimensional dilute Bose quantum fluid evolve in time. They
consequently display a strongly renormalized dispersion law, of Bogoliubov
type. Analytical and numerical results are found in both the absence and the
presence of one- and two-photon losses. Silicon and silicon-nitride waveguides
are used as examples. We finally propose an experiment to measure this
Bogoliubov dispersion relation, based on a stimulated four-wave mixing and
interference spectroscopy techniques.Comment: 17 pages, 7 figure
Quantum fluctuations around black hole horizons in Bose-Einstein condensates
We study several realistic configurations allowing to realize an acoustic
horizon in the flow of a one dimensional Bose-Einstein condensate. In each case
we give an analytical description of the flow pattern, of the spectrum of
Hawking radiation and of the associated quantum fluctuations. Our calculations
confirm that the non local correlations of the density fluctuations previously
studied in a simplified model provide a clear signature of Hawking radiation
also in realistic configurations. In addition we explain by direct computation
how this non local signal relates to short range modifications of the density
correlations