“From quantum information to particle physics via tensor network and quantum simulations”
Quantum information concepts become increasingly important in condensed matter, particle and gravitational physics as a joint effort. In particular, they can provide new insights for the understanding of emergent phenomena of QFTs under extreme conditions, which often pose significant challenges for their theoretical treatment. As one such example, I consider in this talk the melting of mesons as nonperturbative bound states at high temperatures. This process is relevant for the phenomenological description of nuclear collisions and in its inverse form for the understanding of the quark-gluon plasma in the early universe. While QCD and holographic approaches indicate the melting process through a thermal broadening of in-medium spectral functions, we want to motivate a new paradigm here by studying entanglement properties. As a first step in this direction, we employ tensor network techniques to study entanglement entropies in a static and dynamical setting (generated through a quantum quench) of the two-dimensional Ising QFT. We explain observed features at high enough temperatures through the fact that meson states in the quantum many-body system are melted and argue that the considered entanglement measures can serve as a witness of that process. We then explore the capabilities of analog quantum simulations with trapped ions to detect relativistic meson spectra on current devices. Such simulations open the prospect to study fundamental physical effects beyond the capability of classical resources. Following this line of research, I shortly motivate future explorations of higher-dimensional gauge theories and further quantum quench studies.