JQI

Abstract: Superconductivity in the limit of a vanishing bandwidth in isolated bands is a classic example of a non-perturbative problem, where BCS theory does not apply. What sets the superconducting phase stiffness, and relatedly the transition temperature, in this limit is of both fundamental and practical interest. This question has become especially relevant with the discovery of superconductivity in moiré materials.

Abstract: Over the past decade, advances in atomic, molecular, and optical (AMO) physics techniques enabled the cooling of simple molecules down to the ultracold regime (< 1 mK), allowing unprecedented control over their quantum states. This opened a host of new opportunities in quantum information, precision measurement, and controlled chemistry. I will discuss two experiments on precisely probing and controlling inter- and intramolecular dynamics at ultralow temperatures, respectively.

(Pizza and refreshments will be served after the talk.)

(Pizza and refreshments will be served after the talk.)

A quantum state that depends on a parameter is a commonly studied structure in quantum physics. Examples include the ground state of a Hamiltonian with a parameter or Bloch states as functions of the quasimomentum. The change in the state as the parameter varies can be characterized by such geometric objects as the Berry phase or the quantum distance which has led to many insights in the understanding of quantum systems.

I will describe a recent quantum algorithm (arXiv:2303.13012) for simulating the classical dynamics of 2^n coupled oscillators (e.g., 2^n masses coupled by springs). The algorithm is based on a mapping between the Schr\"odinger equation and Newton's equations for harmonic potentials such that the amplitudes of the evolved quantum state encode the momenta and displacements of the classical oscillators.