Quantum simulation of Unruh-DeWitt detectors with nonlinear optics

Abstract

We propose a method for simulating an Unruh-DeWitt detector, coupled to a 1+1-dimensional massless scalar field, with a suitably-engineered χ (2) nonlinear interaction. In this simulation, the parameter playing the role of the detector acceleration is played by the relative inverse-groupvelocity gradient inside the nonlinear material. We identify experimental parameters that tune the detector energy gap, acceleration, and switching function. This system can simulate time-dependent acceleration, time-dependent detector energy gaps, and non-vacuum initial detector-field states. Furthermore, for very short materials, the system can simulate the weak anti-Unruh effect, in which the response of the detector decreases with acceleration. While some Unruh-related phenomena have been investigated in nonlinear optics, this is the first proposal for simulating an Unruh-DeWitt detector in these systems.

Unruh-DeWitt detector in dimensionally-reduced static spherically symmetric spacetimes

“…Since the truncated metric is non-dynamical (and is not required to be a solution of some two-dimensional theory), one can ask if there is a clever, even if ad hoc, trick to incor-porate the effect of rotation (angular momentum) such as that of Kerr black hole 18 , or the effect of gravitational waves. Since there are not enough spatial dimensions, there can be no rotating black hole in (1+1) dimensions nor gravitational waves.…”

“…They are now refined to a point where finite-size effects are included in a covariant manner [3][4][5] and capture the impact of quantized centre-of-mass degrees of freedom of the detector [6]. These models also admit "variants": these include non-linear interactions [7], different spins of both the detector and the field [8], harmonic oscillatorbased detectors [9][10][11][12], spacetime superpositions [13][14][15], quantum causal switches [16], and even experimental models using lasers [17] and non-linear optics [18]. Within the subject matter now known as relativistic quantum information (RQI), particle detector models are now developed enough to provide a local measurement theory for QFT that respects causality [19].…”

Unruh-DeWitt detector in dimensionally-reduced static spherically symmetric spacetimes

“…Since the truncated metric is non-dynamical (and is not required to be a solution of some two-dimensional theory), one can ask if there is a clever, even if ad hoc, trick to incorporate the effect of rotation (angular momentum) such as that of Kerr black hole, 18 or the effect of gravitational waves. Since there are not enough spatial dimensions, there can be no rotating black hole in (1+1) dimensions nor gravitational waves.…”

“…They are now refined to a point where finite-size effects are included in a covariant manner [3][4][5] and capture the impact of quantized centre-of-mass degrees of freedom of the detector [6]. These models also admit "variants": these include non-linear interactions [7], different spins of both the detector and the field [8], harmonic oscillatorbased detectors [9][10][11][12], spacetime superpositions [13][14][15], quantum causal switches [16], and JHEP03(2022)014 even experimental models using lasers [17] and non-linear optics [18]. Within the subject matter now known as relativistic quantum information (RQI), particle detector models are now developed enough to provide a local measurement theory for QFT that respects causality [19].…”

Unruh and analogue Unruh temperatures for circular motion in 3+1 and 2+1 dimensions

“…A direct experimental confirmation of the effect has however remained elusive because of the required magnitude of the acceleration [7]. Prospects to observe versions of the effect in high-power laser systems are discussed in [8,9,10,11,12,13,14], and a selection of other experimental proposals are discussed in [15,16,17,18,19,20]. Within the analogue spacetime programme of simulating relativistic phenomena in nonrelativistic laboratory systems [21,22], an indirect experiment relying on virtual observers was reported in [23] and an indirect experiment relying on functional equivalence was reported in [24].…”