On the observation of nonclassical excitations in Bose–Einstein condensates

  title={On the observation of nonclassical excitations in Bose–Einstein condensates},
  author={Andreas Finke and Piyush Jain and Silke E. Ch. Weinfurtner},
  journal={New Journal of Physics},
In the recent experimental and theoretical literature well-established nonclassicality criteria from the field of quantum optics have been directly applied to the case of excitations in matter-waves. Among these are violations of Cauchy–Schwarz inequalities, Glauber–Sudarshan P-nonclassicality, sub-Poissonian number-difference squeezing (also known as the two-mode variance) and the criterion of nonseparability. We review the strong connection of these criteria and their meaning in quantum… 

Phonon spectrum and correlations in a transonic flow of an atomic Bose gas

Motivated by a recent experiment of J. Steinhauer, we reconsider the spectrum and the correlations of the phonons spontaneously emitted in stationary transonic flows. The latter are described by

Low-frequency analogue Hawking radiation: The Bogoliubov-de Gennes model

We analytically study the low-frequency properties of the analogue Hawking effect in Bose-Einstein condensates. We show that in one-dimensional flows displaying an analogue horizon, the Hawking

Analogue quantum simulation of the Hawking effect in a polariton superfluid

Quantum effects of fields on curved spacetimes may be studied in the laboratory thanks to quantum fluids. Here we use a polariton fluid to study the Hawking effect, the correlated emission from the

Analytical description of quantum emission in optical analogs to gravity

We consider a moving refractive index perturbation in an optical medium as an optical analogue to waves under the influence of gravity. We describe the dielectric medium by the Lagrangian of the

Momentum correlations as signature of sonic Hawking radiation in Bose-Einstein condensates

We study the two-body momentum correlation signal in a quasi one dimensional Bose-Einstein condensate in the presence of a sonic horizon. We identify the relevant correlation lines in momentum space

Departing from Thermality of Analogue Hawking Radiation in a Bose-Einstein Condensate.

The taking into account of evanescent channels and of zero modes makes it possible to accurately reproduce recent experimental measurements of the density correlation function, and the determination of Hawking temperature is discussed.

On the role of interactions in trans-sonically flowing atomic condensates

We provide a joint numerical-analytical study of the physics of a flowing atomic Bose-Einstein condensate in the combined presence of an external trap and a step potential which accelerates the atoms

Density correlations from analog Hawking radiation in the presence of atom losses

The sonic analogue of Hawking radiation can now be experimentally recreated in Bose-Einstein Condensates that contain an acoustic black hole. In these experiments the signal strength and analogue

Thermal noise in BEC-phononic gravitational wave detectors

Quasiparticles in a Bose-Einstein condensate are sensitive to space-time distortions. Gravitational waves can induce transformations on the state of phonons that can be observed through quantum state

Towards a Gordon form of the Kerr spacetime

It is not currently known how to put the Kerr spacetime metric into the so-called Gordon form, although the closely related Kerr–Schild form of the Kerr metric is well known. A Gordon form for the



On the robustness of entanglement in analogue gravity systems

We investigate the possibility of generating quantum-correlated quasi-particles utilizing analogue gravity systems. The quantumness of these correlations is a key aspect of analogue gravity effects

Simulations of thermal Bose fields in the classical limit

We demonstrate that the time-dependent projected Gross-Pitaevskii equation (GPE) derived earlier [M. J. Davis, R. J. Ballagh, and K. Burnett, J. Phys. B 34, 4487 (2001)] can represent the highly

Bound-state signatures in quenched Bose-Einstein condensates

We investigate the dynamics of a homogenous Bose-Einstein condensate (BEC) following a sudden quench of the scattering length. Our focus is the time evolution of short-range correlations via the

Dissipative fields in de Sitter and black hole spacetimes: quantum entanglement due to pair production and dissipation

For free fields, pair creation in expanding universes is associated with the building up of correlations that lead to nonseparable states, i.e., quantum mechanically entangled ones. For dissipative

Theory of Bose-Einstein condensation in trapped gases

The phenomenon of Bose-Einstein condensation of dilute gases in traps is reviewed from a theoretical perspective. Mean-field theory provides a framework to understand the main features of the

From Cosmology to Cold Atoms: Observation of Sakharov Oscillations in a Quenched Atomic Superfluid

The observation of Sakharov oscillations in the density fluctuations of a quenched atomic superfluid is reported through a systematic study in both space and time domains and with tunable interaction strengths to suggest a different approach to the study of nonequilibrium dynamics of quantum many-body systems and the exploration of their analogs in cosmology and astrophysics.

Quantum entanglement in analogue Hawking radiation: When is the final state nonseparable?

We study the quantum entanglement of the quasiparticle pairs emitted by analogue black holes. We use a phenomenological description of the spectra in dispersive media to study the domains in

Violation of the Cauchy-Schwarz inequality with matter waves.

Four-wave mixing of atomic matter waves using colliding Bose-Einstein condensates is realized, and the violation of a multimode CS inequality for atom number correlations in opposite zones of the collision halo is demonstrated.

Entanglement and violation of classical inequalities in the Hawking radiation of flowing atom condensates

We consider a sonic black-hole scenario where an atom condensate flows through a subsonic–supersonic interface. We discuss several criteria that reveal the existence of non-classical correlations

Analog model of a Friedmann-Robertson-Walker universe in Bose-Einstein condensates: Application of the classical field method

Analog models of gravity have been motivated by the possibility of investigating phenomena not readily accessible in their cosmological counterparts. In this paper, we investigate the analog of