Talks

I will present a calculation of the vacuum energy that reproduces the observed value and that points to a completely new understanding of quantum gravity as gravitized quantum theory. In that context the fixed Born rule becomes dynamical. After a short conceptual background, I will discuss experimental consequences of this new viewpoint involving intrinsic triple and higher order quantum interferences that are impossible in quantum mechanics and quantum field theory. Also, I will indicate how the observed masses of quarks and leptons (including predictions for the neutrino masses) as well as their mixing angles could be understood in the same context. At the very end I also plan to comment on a time-varying dark energy as another prediction of quantum gravity viewed as gravitized quantum theory.

[This talk is based on the following papers:

https://arxiv.org/pdf/2212.00901

https://arxiv.org/pdf/2407.06207

https://arxiv.org/pdf/2501.19269 ]

The ground state of a bipartite quantum system resembles a thermal state from the perspective of an observer with access to only one of the two regions. This observation has led to the introduction of the entanglement Hamiltonian, which has numerous applications in quantum information and the study of quantum many-body systems.

 

This talk will explore two approaches to computing the entanglement Hamiltonian: one in the context of quantum field theories (QFTs), focusing on the Bisognano-Wichmann Hamiltonian, and the other for free fermion models on a lattice, where connections with algebraic Heun operators will be highlighted. Additionally, the relationship between the discrete and continuum cases will be examined.

Quantum codes with transversal non-Clifford gates have many applications in fault tolerant quantum computation, from magic state distillation to robust IQP circuit sampling.

In the past year, there has been spectacular progress on constructing such codes with optimal parameter scaling, i.e., constant encoding rate and constant relative distance.

These constructions rely on quantum versions of algebraic geometry codes, which generalise the well-known Reed-Solomon and Reed-Muller codes.

In this talk, we will describe one such construction that yields a family of good codes with a transversal control-control-Z gate, and we will highlight some of the remaining open problems in this area.