Steady many-body entanglements in dissipative systems

Abstract

We propose a dissipative method for the preparation of many-body steady entangled states in spin and fermionic chains. The scheme is accomplished by means of an engineered set of Lindbladians acting over the eigenmodes of the system, whose spectrum is assumed to be resolvable. We apply this idea to prepare a particular entangled state of a spin chain described by the XY model, emphasizing its generality and experimental feasibility. Our results show that our proposal is capable of achieving high fidelities and purities for a given target state even when dephasing and thermal dissipative processes are taken into account. Moreover, the method exhibits a remarkable robustness against fluctuations in the model parameters.Comment: 7 pages, 2 figure

Ground-state cooling of a nanomechanical oscillator with N spins

“…where, Ŝ is the symmetrization operator. As mentioned, even though we have found some other distributions of c s and d s where our protocol still work (e.g., a Gaussian distribution), we would like to focus our attention in states of experimental interests (or theoretical proposals to achieve them) ( [42][43][44][45][46][47][48] and references therein), such as the symmetric coherent spin state (a = b = 1/ √ 2)…”

Initialization of quantum simulators by sympathetic cooling

“…Our strategy to overcome this problem builds on the recent advances in using dissipative quantum systems to engineer interesting many-body states as the attractor states of such an open quantum many-body system (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). In the past, these dissipative state engineering schemes have been limited to ground states of stabilizer or frustration-free Hamiltonians (16,17,26,27), whose ground state can be found by performing local optimizations alone.…”

“…Crucially, the energy splitting within the auxiliary particle is chosen such that it becomes resonant with the many-body excitation gap of the system of interest, i.e., the difference of the ground-state energy and the energy of the first excited state. Under such a resonance condition, the energy of the quantum simulator is efficiently transferred to the auxiliary particle such that the former is cooled sympathetically (23,25). Although this setup is only resonant at a single energy, the density of states increases exponentially with energy, resulting in the lowest-lying excitations being the bottleneck for fast ground-state preparation (see the Supplementary Materials for details).…”

Engineering Knill–Laflamme–Milburn Entanglement via Dissipation and Coherent Population Trapping in Rydberg Atoms

“…Cole et al [34] discussed a scheme that uses sympathetic cooling as the dissipation mechanism and relies on tailored destructive interference to generate anyone of six entangled W states in a three-ion qubit space. Furthermore, dissipative preparation has been generalized to high-dimensional, [35,36] multipartite, [37][38][39][40][41] and distant entanglements. [42] According to the previous reports, dissipative preparation has been realized in various experimental platforms, including superconductors, [43,44] photons, [45,46] quantum dots, [47] nitrogen-vacancy centers, [48] neutral atoms, [49,50] and trapped ions.…”