Talks

I will discuss our work ("Traversable wormhole dynamics on a quantum processor", Nature) on interrogating a two-dimensional gravity dual quantum system on-chip, and implications on future exploration of this type. I will also address comments/objections raised recently in the literature (https://arxiv.org/abs/2303.15423)

Bubble nucleation in a cold spin 1 gas (Kate Brown); Bubbles live fast and stick together (Dalila Pirvu); Superfluid helium vortex flow: Experimental realization (Pietro Smaniotto); Superfluid helium vortex flow: Surface reconstruction (Leonardo Solidoro); Acceleration-induced effects in stimulated light-matter interactions (Barbara Soda) ZOOM:https://pitp.zoom.us/j/95722860808?pwd=REYwSDdiK3pFamRJcjJwOW5FV1RPZz09

Complementing the spectacular breakthroughs in gravitational wave and multi-messenger astronomy, advancements in our theoretical understanding and modelling of the strong gravity are essential to apprehending the nonlinear dynamics of spacetime, and to unlocking the full potential of the observations. I will illustrate the scope of new physics that might be probed by black holes, neutron stars, and other such systems, including testing general relativity and strong gravity signatures of new particles, and describe some recent developments that allow for uncovering novel phenomena and making detailed predictions in this regime.

Zoom Link: https://pitp.zoom.us/j/96180256322?pwd=LzEyd3ZBWGdZeDR6MjB1dGpLWFRpUT09

Systems in thermal equilibrium at non-zero temperature are described by their Gibbs state. For classical many-body systems, the Metropolis-Hastings algorithm gives a Markov process with a local update rule that samples from the Gibbs distribution. For quantum systems, sampling from the Gibbs state is significantly more challenging. Many algorithms have been proposed, but these are more complex than the simple local update rule of classical Metropolis sampling, requiring non-trivial quantum algorithms such as phase estimation as a subroutine.

Here, we show that a dissipative quantum algorithm with a simple, local update rule is able to sample from the quantum Gibbs state. In contrast to the classical case, the quantum Gibbs state is not generated by converging to the fixed point of a Markov process, but by the states generated at the stopping time of a conditionally stopped process. This gives a new answer to the long-sought-after quantum analogue of Metropolis sampling. Compared to previous quantum Gibbs sampling algorithms, the local update rule of the process has a simple implementation, which may make it more amenable to near-term implementation on suitable quantum hardware. We also show how this can be used to estimate partition functions using the stopping statistics of an ensemble of runs of the dissipative Gibbs sampler. This dissipative Gibbs sampler works for arbitrary quantum Hamiltonians, without any assumptions on or knowledge of its properties, and comes with certifiable precision and run-time bounds.
This talk is based on 2304.04526, completed in collaboration with Jan-Lukas Bosse and Toby Cubitt.

Zoom Link: https://pitp.zoom.us/j/96780945341?pwd=NG9SUjE4SkVia3VqazNXUFNUamhRdz09

 

 

It has long been known in studies of Pion physics, non-linear sigma models and cosmology that thinking in terms of field space metrics can be useful. Such an approach can help identify and define field redefinition invariant physics in observables. This approach is reemerging recently an a key organizing principle and calculational tool for interpreting collider physics data to study Higgs properties. I will review some known results and discuss outstanding issues being worked on in this area. 

Zoom Link: https://pitp.zoom.us/j/96662488113?pwd=cGs0THQwWXRkcm9pVzcwVytnNjZ5Zz09