Initialization of quantum simulators by sympathetic cooling

Abstract

Simulating computationally intractable many-body problems on a quantum simulator holds great potential to deliver novel insights into physical, chemical, and biological systems. While the implementation of Hamiltonian dynamics within a quantum simulator has already been demonstrated in many experiments, the problem of initialization of quantum simulators to a suitable quantum state has hitherto remained mostly unsolved. Here, we show that already a single dissipatively driven auxiliary particle can efficiently prepare the quantum simulator in a low-energy state of largely arbitrary Hamiltonians. We demonstrate the scalability of our approach and show that it is robust against unwanted sources of decoherence. While our initialization protocol is largely independent of the physical realization of the simulation device, we provide an implementation example for a trapped ion quantum simulator.

Dissipative preparation of W states in trapped ion systems

“…As a consequence, the fidelities predicted by numerical simulations are comparable to those achievable with unitary schemes [25]. Future efforts may explore these concepts beyond state preparation, such as in new protocols for autonomous quantum error correction and quantum sensing [19], as well as for quantum simulation [20,59].…”

“…Dissipative protocols for generation and stabilization of entangled and other nonclassical states have been demonstrated in a number of systems, including macroscopic atomic ensembles [4], trapped ions [5][6][7], and superconducting qubits [8][9][10]. Numerous proposals describe additional schemes to generate entanglement [11][12][13][14][15][16][17], perform error correction [18,19], and initialize quantum simulators [20]. Broadly, the full scope over which engineered dissipation may be applied for quantum information processing is not yet clear, and practical protocols that can accomplish new tasks expand the frontier.…”

Dissipative cooling induced by pulse perturbations

“…As a consequence, in our model the transient cooling does not suffer from the stringent limitations given, e.g., by the microwave cavity decay rate, which strongly affect optomechanical cooling, and make challenging its experimental realisation [34]. We finally mention recent works [35][36][37] that show how properly designed dissipative protocols can efficiently prepare a quantum system in its ground state. Therefore, tailoring dissipation may represent a novel tool to control open many-body systems, including the selective cooling that we have here discussed.…”

Dissipative generation of pure steady states and a gambler's ruin problem

“…Deep understanding of the quantum part of the criterion remains a challenge for the future. From the applicative viewpoint, our criterion allows dissipative targeting of pure states or simple mixtures of few quantum states, a task of fundamental importance in the initialization of quantum simulators [32] (see also [33] for an up-to-date review of recent and ongoing experiments).…”