Abstract

In 2019, it was experimentally demonstrated that a quantum processor could perform certain computational tasks exponentially faster than a classical computer [1]. Going beyond this milestone, we seek to utilize these Noisy Intermediate Scale Quantum (NISQ) processors to study computationally intractable physics problems, such as systems of interacting particles. One of the hallmarks of interacting systems is the formation of multi-particle bound states. In a ring of 24 superconducting qubits, we implement the periodic quantum circuit of the spin-1/2 XXZ model, an archetypal model of interaction [2]. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the common wisdom that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit. If time permits, I will discuss another recent project which elucidates the noise sensitivity of symmetry-protected Majorana edge modes in a solid-state environment [3].

[1] Nature 574, 505–510 (2019) [2] arXiv: 2206.05254 [3] arXiv: 2204.11372