Analogue black holes in relativistic BECs: Mimicking Killing and universal horizons

Abstract

Relativistic Bose-Einstein condensates (rBECs) have recently become a wellestablished system for analogue gravity. Indeed, while such relativistic systems cannot be yet realized experimentally, they provide an interesting framework for mimicking metrics for which no analogue is yet available, so paving the way for further theoretical and numerical explorations. In this vein, we here discuss black holes in rBECs and explore how their features relate to the bulk properties of the system. We then propose the coupling of external fields to the rBEC as a way to mimic non-metric features. In particular, we use a Proca field to simulate an aether field, as found in Einstein-AEther or Hořava-Lifshitz gravity. This allows us to mimic a universal horizon, the causal barrier relevant for superluminal modes in these modified gravitational theories.

Rotating black hole solutions in relativistic analogue gravity

“…and that in the limit a → 0 both the horizon and the ergosurface move to the position of the horizon of the canonical static acoustic black hole presented in [9]. Representation of the streamlines of the normalized 4-current for ξ = 0.9, u0 = c, r0 = 0 and a = 0.8b (expressed with respect to an orthonormal vector basis) on a vertical slice of the space (that is at φ = const).…”

“…In [9] it was shown how static metric solutions can be incorporated in the formalism of relativistic acoustic spacetimes. We now focus on stationary axisymmetric solutions, having in mind rotating black holes.…”

“…They hence provide a potentially more versatile framework for simulating interesting spacetimes. It has already been shown that analogues of static black hole spacetimes both in the asymptotically flat and asymptotically (A)dS cases [10,16,17] can be obtained in relativistic condensates, and also cosmological metrics and structures of alternative theories of gravitation can be studied [9]. The main scope of this article is to understand if also rotating black holes spacetimes can fit in relativistic analogues and to study their relationship with the non-relativistic solutions.…”

Analogue simulation of gravitational waves in a 3+1 -dimensional Bose-Einstein condensate

“…We have studied GWs in the context of perturbations around a flat spacetime metric and assuming GWs to be far outside the source. Other interesting simulations could involve GWs propagating on curved backgrounds, such as black holes [9,10] or during inflation [43], or in strong-field regimes. Furthermore, since phonons are quantum quasi-particles, this opens up the possibility of studying predicted effects of quantum field theory in curved spacetime, such as how a GW may affect the entanglement of quantum systems, a phenomena that is utilised in the BEC GW detector proposed in [25].…”

Quantum simulation of dark energy candidates

“…Excerpts from this catalogue of analogue models include conformal Schwarzschild black holes [26,27], rotating black holes [28], Bañados-Teitelboim-Zanelli (BTZ) black holes [29], Friedmann-Robertson-Walker geometries [30,31], inflation [32,33] and extensions to general relativity such as aether fields [26]. Three of us have extended this catalogue to include gravitational wave space-times [34,35].…”