Seminar featuring Hui Wang, Dartmouth College
In the Unruh Effect (UE) a uniformly accelerating observer (photodetector) is expected to ’see' thermal photons in vacuum while an inertial observer would see none. A longstanding challenge to demonstrate the UE in the lab is that a photodetector's required proper acceleration seems impossibly high for any current or planned table top experiment. In this presentation, we describe two complementary ways to realize close analogues of the UE that overcome the apparent need for large proper accelerations. In the first approach, we consider a superconducting circuit QED set-up that involves an oscillating (i.e. accelerating) centre of mass photon detector modeled as either a harmonic oscillator or a qubit that is capacitively coupled to a microwave cavity mode via a mechanically oscillating, GHz film bulk acoustic resonator (FBAR). We show that the oscillator (qubit) photodetector-cavity system maps onto a simple non-degenerate parametric amplifier model. Under certain resonance conditions between the mechanical, cavity, and detector frequencies, there is a significant enhancement in the detector excitation and vacuum cavity photon number production rates, a consequence of achievable large cavity-detector FBAR capacitive couplings and superconducting cavity quality factors.
In the second approach, we consider N>>1 oscillating centre of mass photon detectors modeled as two level systems (TLS) that are independently coupled to the cavity mode; the photon-detector system resembles a parametrically driven Dicke-type model. When the TLS number N exceeds a certain critical value, the TLS-cavity mode system undergoes a quantum phase transition, where the photon production rate changes from a so-called normal phase to a symmetry broken superradiant phase in which the rate is significantly further enhanced such as to be potentially measurable. As a possible concrete realization, we consider a mechanical membrane with a dense concentration of NV centre defects undergoing GHz flexural motion, and contained within a 3D high quality factor, superconducting microwave cavity.
Bio: Hui Wang is a PhD Candidate in the Department of Physics and Astronomy at Dartmouth College. Her research interests are in relativistic quantum information with applications to superconducting circuits and optomechanical systems. Specific projects have looked at quantum properties such as vacuum amplification processes within nonlinear superconducting cavity systems, the investigation of such processes within a relative quantum reference frame perspective, and Dicke superradiant-like enhancements of the Unruh effect.
Event address for attendees: https://uwaterloo.webex.com/uwaterloo/onstage/g.php?MTID=e8fa13e9fe16e6ea9bf5b4c64834f4844
Event number (access code): 160 548 9671
Event password: D5MnAum4wb3