Kavli Affiliate: Ke Wang
| First 5 Authors: Feitong Jin, Si Jiang, Xuhao Zhu, Zehang Bao, Fanhao Shen
| Summary:
Symmetry-protected topological phases cannot be described by any local order
parameter and are beyond the conventional symmetry-breaking paradigm for
understanding quantum matter. They are characterized by topological boundary
states robust against perturbations that respect the protecting symmetry. In a
clean system without disorder, these edge modes typically only occur for the
ground states of systems with a bulk energy gap and would not survive at finite
temperatures due to mobile thermal excitations. Here, we report the observation
of a distinct type of topological edge modes, which are protected by emergent
symmetries and persist even up to infinite temperature, with an array of 100
programmable superconducting qubits. In particular, through digital quantum
simulation of the dynamics of a one-dimensional disorder-free "cluster"
Hamiltonian, we observe robust long-lived topological edge modes over up to 30
cycles at a wide range of temperatures. By monitoring the propagation of
thermal excitations, we show that despite the free mobility of these
excitations, their interactions with the edge modes are substantially
suppressed in the dimerized regime due to an emergent U(1)$times$U(1)
symmetry, resulting in an unusually prolonged lifetime of the topological edge
modes even at infinite temperature. In addition, we exploit these topological
edge modes as logical qubits and prepare a logical Bell state, which exhibits
persistent coherence in the dimerized and off-resonant regime, despite the
system being disorder-free and far from its ground state. Our results establish
a viable digital simulation approach to experimentally exploring a variety of
finite-temperature topological phases and demonstrate a potential route to
construct long-lived robust boundary qubits that survive to infinite
temperature in disorder-free systems.
| Search Query: ArXiv Query: search_query=au:”Ke Wang”&id_list=&start=0&max_results=3