Lecture series: Barbara SODA

(1) Tuesday, November 12, 4:30 PM:

Trajectory-protected quantum computing

We demonstrate a quantum computing model that utilizes a qubit’s motion to protect it from decoherence. We model a qubit interacting with a quantum field via the standard light-matter interaction model: an Unruh-DeWitt detector, i.e. the qubit, follows a prescribed classical trajectory while interacting with a scalar quantum field.  We switch off the rotating-wave terms, i.e. the resonant transitions, by controlling the trajectory of the qubit, thereby eliminating decoherence via dominant channels of decoherence. This phenomenon is known as acceleration-induced transparency. We use the stimulated counter-rotating wave terms (i.e. the non-resonant transitions) to perform one-qubit gates. The two-qubit, entangling, gates are performed by vacuum interaction related to entanglement harvesting, where we make use of control via squeezed state stimulation of the field. We find that the error protection due to trajectory control hinders entanglement creation via two-qubit gates. Finally, we discuss the fundamental limits on the trade-off between isolating a quantum computer, and the speed with which entangling gates may be applied.

Chair: Andreas Buchleitner

(2) Wednesday, November 13, 1:00 PM:

Newton’s Cradle Spectra

When we try to understand phenomena arising from non-perturbative interactions, we often find that our toolbox is lacking. I will introduce Newton’s cradle spectra as a new tool for studying non-perturbative interactions, based on the preprint: arXiv:2206.09927. I will then go through examples of how it may be applied, and explain how it can be utilized to study entanglement generation and transfer, based on: arXiv:2407.18301.

Chair: Andreas Buchleitner

(3) Thursday, November 14, 6:00 PM:

Superoscillations

I will introduce the phenomenon of superoscillations, explain how, in quantum physics, they arise from anomalous weak values, and discuss several applications of it. I will talk about recent progress in superresolution, especially research described in PRL 131, 053803 (2023). 

Chair: Andreas Buchleitner