We report on the observation of negative differential conductivity (NDC) in a quantum transport device for neutral atoms employing multimode tunneling junction. The system is realized with Bose-Einstein condensate loaded one-dimensional optical lattice high site occupancy. induce an initial difference chemical potential at one by local atom removal. ensuing dynamics are governed interplay between coupling, interaction energy, and intrinsic collisions, which turn coherent coupling into...

We present a discrete-time, one-dimensional quantum walk based on the entanglement between momentum of ultracold rubidium atoms (the space) and two internal atomic states "coin" degree freedom). Our scheme is highly flexible can provide platform for wide range applications such as search algorithms, observation topological phases, realization walks with higher dimensionality. Along investigation quantum-to-classical transition, we demonstrate distinctive features contrast them to those its...

We show that molecular nanomagnets have a potential advantage in the crucial rush toward quantum computers. Indeed, sizable number of accessible low-energy states these systems can be exploited to define qubits with embedded error correction. derive scheme achieve this objective and corresponding sequence microwave/radiofrequency pulses needed for correction procedure. The effectiveness our approach is shown already minimal S = 3/2 unit an existing molecule, scaling larger spin...

We report time-resolved measurements of Landau-Zener tunneling Bose-Einstein condensates in accelerated optical lattices, clearly resolving the steplike time dependence band populations. Using different experimental protocols we were able to measure probability both adiabatic and diabatic bases system. also experimentally determine contribution momentum width Bose temporal steps discuss implications for measuring jump problem.

We investigate the effects of phase noise and particle loss on dynamics a Bose-Einstein condensate in an optical lattice. Starting from many-body master equation, we discuss applicability generalized mean-field approximations presence dissipation as well methods to simulate quantum beyond by including higher-order correlation functions. It is shown that localized leads surprising dynamics, it can suppress decay restore coherence condensate. These be applied engineer coherent structures such...

We discuss the dynamics of a Bose-Einstein condensate in double-well trap subject to phase noise and particle loss. The coherence weakly interacting as well response an external driving show pronounced stochastic resonance effect: Both quantities become maximal for finite value dissipation rate matching intrinsic time scales system. Even stronger effects are observed when acts concurrence with strong interparticle interactions, restoring purity almost completely increasing significantly.

Abstract Synchronization and entanglement constitute fundamental collective phenomena in multi-unit classical quantum systems, respectively, both equally implying coordinated system states. Here, we present a direct link for class of isolated many-body demonstrating that synchronization emerges as an intrinsic feature. Intriguingly, coherence arise persistently through the same transition synchronization. This between cooperative may further our understanding strongly correlated systems can...

The quantum resonances occurring with δ-kicked atoms when the kicking period is an integer multiple of half-Talbot time are analysed in detail. Exact results about momentum distribution at exact resonance established, both case totally coherent dynamics and decoherence induced by spontaneous emission. A description close to, but not exactly resonance, derived means a quasi-classical approximation where detuning from plays role Planck constant. In this way scaling laws describing shape...

We report on measurements of resonantly enhanced tunneling Bose-Einstein condensates loaded into an optical lattice. By controlling the initial conditions our system we were able to observe resonant in ground and first two excited states lattice wells. also investigated effect intrinsic nonlinearity condensate resonances.

We propose a method to produce fast transitionless dynamics for finite-dimensional quantum systems without requiring additional Hamiltonian components not included in the initial control setup, remaining close true adiabatic path at all times. The strategy is based on introduction of an effective counterdiabatic scheme: correcting constructed which approximatively cancels nonadiabatic effects, inducing evolution tracking states closely. This can be absorbed into by adding oscillation...

Molecular Nanomagnets may enable the implementation of qudit-based quantum error-correction codes which exploit many spin levels naturally embedded in a single molecule, promising step towards scalable processors. To fully realize potential this approach, microscopic understanding errors corrupting information encoded molecular qudit is essential, together with development tailor-made error correction strategies. We address these central points by first studying dephasing effects on produced...

Each step in a quantum random walk is typically understood to have two basic components; `coin-toss' which produces superposition of states, and displacement moves each component the by different amounts. Here we suggest realization momentum space with spinor Bose-Einstein condensate subject ratchet realized pulsed, off-resonant optical lattice. By an appropriate choice lattice detuning, show how atomic can be entangled internal spin states atoms. For coin-toss, propose use microwave pulse...

The realization of effective Hamiltonians featuring many-body interactions beyond pairwise coupling would enable the quantum simulation central models underpinning topological physics and computation. We overcome crucial limitations perturbative Floquet engineering discuss highly accurate a purely three-body Hamiltonian in superconducting circuits molecular nanomagnets.

A scalable architecture for quantum computing requires logical units supporting quantum-error correction. In this respect, magnetic molecules are particularly promising, since they allow one to define qubits with embedded correction by exploiting multiple energy levels of a single molecule. The single-object nature encoding is expected facilitate the implementation error procedures and operations. work, we make progress in direction showing how two-qubit gates between error-protected can be...

We discuss the dynamics of a Bose-Einstein condensate in double-well trap subject to phase noise and particle loss. The coherence weakly interacting condensate, experimentally measured via contrast an interference experiment, as well response external driving becomes maximal for finite value dissipation rate matching intrinsic time scales system. This can be understood stochastic resonance many-particle Even stronger effects are observed when acts concurrence with strong interparticle...

We analyze the decay of ultracold atoms from an optical lattice with loss a single site. If initial state is dynamically stable, suitable amount dissipation can stabilize Bose-Einstein condensate, such that it remains coherent even in presence strong interactions. A transition between two dynamical phases observed if unstable. This analyzed here detail. For interactions, system relaxes to entangled quantum remarkable statistical properties: The bunch few ``breathers'' forming at random...

We theoretically propose a quantum simulation scheme for the toric-code Hamiltonian, paradigmatic model of spin liquid, based on time-periodic driving. develop hybrid continuous-digital strategy that exploits commutativity different terms in target Hamiltonian. It allows one to realize required four-body interactions nonperturbative way, attaining strong coupling and suppression undesired processes. In addition, we design an optimal protocol preparing topologically ordered ground states with...

The quantum resonances occurring with delta-kicked particles are studied the help of a fictitious classical limit, establishing direct correspondence between nearly resonant motion and related system. A scaling law which characterizes structure peaks is derived numerically demonstrated.

Our realistic numerical results show that the fundamental and higher-order quantum resonances of delta-kicked rotor are observable in state-of-the-art experiments with a Bose condensate shallow harmonic trap, kicked by spatially periodic optical lattice. For stronger confinement, interaction-induced destruction resonant motion oscillator is predicted.

In this paper, we present the theoretical as well experimental results on resonantly enhanced tunneling of Bose–Einstein condensates in optical lattices both linear case and for small nonlinearities. Our demonstrate usefulness simulating Hamiltonians originally used describing solid-state phenomena.