Stark Many-Body Localization on a Superconducting Quantum Processor

Abstract

Quantum emulators, owing to their large degree of tunability and control, allow the observation of fine aspects of closed quantum many-body systems, as either the regime where thermalization takes place or when it is halted by the presence of disorder. The latter, dubbed many-body localization (MBL) phenomenon, describes the non-ergodic behavior that is dynamically identified by the preservation of local information and slow entanglement growth. Here, we provide a precise observation of this same phenomenology in the case the onsite energy landscape is not disordered, but rather linearly varied, emulating the Stark MBL. To this end, we construct a quantum device composed of thirty-two superconducting qubits, faithfully reproducing the relaxation dynamics of a non-integrable spin model. Our results describe the real-time evolution at sizes that surpass what is currently attainable by exact simulations in classical computers, signaling the onset of quantum advantage, thus bridging the way for quantum computation as a resource for solving out-of-equilibrium many-body problems.

Many-body Hilbert space scarring on a superconducting processor

“…A promising solution is to exploit quantum many-body scarring (QMBS) states that were first discovered in a 51 Rydberg-atom chain [14] and explained based on the effective PXP model [15,16]. While breaking the thermalization rendered ergodicity, the QMBS states are distinct from the quantum states in classically integrable systems and from quantum many-body localized states as well [17][18][19][20]. Theoretically, QMBS states have been studied in diverse systems ranging from the Heisenberg spin [21,22], Affleck-Kennedy-Lieb-Tasaki [23,24], extended Hubbard [25][26][27] and Ising [28] models to frustrated [29,30] and topological [31,32] lattices, quantum Hall systems [33,34], Floquet-driven systems [35,36], systems with a flat band [29,37,38], and two-dimensional systems [39].…”

Many-body localization regime for cavity induced long-range interacting models

“…Without the optical cavity the model (??) reveals the so called Stark many-body localization (SMBL) which has been intensively studied since its discovery for spinless fermions [51,52] as well as for bosons [53,57,79], the experimental verification came with spinful fermions in optical lattice [75] as well as in quantum simulators [80][81][82]. It has been also studied for open systems [83].…”

Many-body localization in tilted and harmonic potentials

“…This model immediately attracted the interest on the theoretic side with a recent suggestion of the existence of scarred states in the strong interaction limit [42]. SMBL was studied experimentally on superconducting quantum processor [40] emulating a spin-1/2 chain in a triangular ladder. To complete the picture, let us also note that SMBL is also addressed recently for open systems [43].…”