Research

Tensor network methods for Quantum Field Theory

I am trying to develop new methods to deal with quantum field theories non perturbatively. The idea is to use tensor networks, objects mostly popular in quantum information and condensed matter theory, powerful yet bound to lattice systems, and bring them to the continuum.

a tensor network state on the left and its until recently elusive continuum on the right

Recently, with Ignacio Cirac, we put forward “continuous tensor network states”, that is quantum field theory states built from a continuous limit of tensor networks. They bring promising non perturbative techniques for quantum field theory.

Measurement and control of quantum systems

I am interested in the way small quantum systems evolve when they are continuously monitored and acted upon.

quantum trajectory of a strongly continuously measured qubits: quantum jumps are decorated with quantum spikes

Foundations of Physics

I am interested in the foundations of physics, and especially the foundations of quantum theory and gravity.

In a fundamentally semiclassical theory of gravity, matter (in grey) is quantum (can have superpositions) while spacetime itself (represented by the yellow grid) is sharp, free of superpositions

I have recently been exploring theories in which gravity is fundamentally not quantum. Since 2015, with Lajos Diosi, we have been working on toy models demonstrating that the common objections to a non quantum yet fundamental theory of gravity do not hold.