Analogue Hawking radiation in nonlinear quantum optics

Abstract

The Hawking effect can be understood as a broad kinematic phenomenon associated with mode behavior near a horizon. While astrophysical black holes produce one specific realization of this radiation, this perspective inspires extensive theoretical and experimental efforts to create event horizons in diverse physical systems to observe the resulting analogue Hawking emission. One of the most successful realizations is the fiber-optical analogue, based on nonlinear quantum optics. In these notes, we introduce and motivate this system while outlining the theoretical concepts underlying the gravitational analogy. Finally, we review key experiments and discuss their impact on the field.

Figures (19)

• Figure 1: Schematic representation of the sonic analogue. The fishes play the role of sound waves. The river flow $v(x)$ changes as its slope changes. Image taken from Aguero.2020.
• Figure 2: A diagram of a black star, where $M$ is the mass of the black star and $m$ and $c$ are the mass and velocity of the hypothetical light particle.
• Figure 3: Ingoing and outgoing modes around a BH horizon $r=r_{\text{S}}$. Ingoing modes (yellow) see nothing special at $r_{\text{S}}$. Outgoing modes are trapped, for $r\leq r_{\text{S}}$, inside the event horizon.
• Figure 4: Toy model of spacetime dispersion with effective harmonic oscillators $\hat{A}_k$ at a distance $\ell_{\text{P}}$.
• Figure 5: Diagram of the system showing the classical or quantum fluctuations over a classical background.