Quantum ultra-cold atomtronics

Abstract

It is known that a semi-classical analysis is not always adequate for atomtronics devices, but that a fully quantum analysis is often necessary to make reliable predictions. While small numbers of atoms at a small number of sites are tractable using the density matrix, a fully quantum analysis is often not straightforward as the system becomes larger. We show that the fully quantum positive-P representation is then a viable calculational tool. We postulate an atomtronic phase-gate consisting of four wells in a Bose-Hubbard configuration, for which the semi-classical dynamics are controllable using the phase of the atomic mode in one of the wells. We show that the quantum predictions of the positive-P representation for the performance of this device have little relation to those found semi-classically, and that the performance depends markedly on the actual quantum states of the initially occupied modes. We find that initial coherent states lead to closest to classical dynamics, but that initial Fock states give results that are quite different. A fully quantum analysis also opens the door for deeply quantum atomtronics, in which properties such as entanglement and EPR (Einstein-Podolsky-Rosen) steering become valuable technical properties of a device.

12 pages, 6 figures, submitted to Phys. Rev A

References in corpus (16)

• Cold bosonic atoms in optical lattices
• Dynamical quantum noise in Bose-Einstein condensates
• Atomtronics: ultracold atom analogs of electronic devices
• A Single Atom Transistor in a 1D Optical Lattice
• Transistor-Like Behavior of a Bose-Einstein Condensate in a Triple Well Potential
• Einstein-Podolsky-Rosen correlations via dissociation of a molecular Bose-Einstein condensate
• Numerical representation of quantum states in the positive-P and Wigner representations
• Matterwave Transport Without Transit
• Open quantum systems approach to atomtronics
• Conditions for Vanishing Central-well Population in Triple-well Adiabatic Transport
• Coherent tunneling via adiabatic passage in a three-well Bose-Hubbard system
• Principles of an Atomtronic Battery
• Quantum dynamics of a four-well Bose-Hubbard model with two different tunneling rates
• Quantum phase-space analysis of population equilibration in multi-well ultracold atomic systems
• Asymmetric steering in coherent transport of atomic population with a three-well Bose-Hubbard model
• Quantum dynamics and entanglement in coherent transport of atomic population

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• Challenges and constraints of dynamically emerged source and sink in atomtronic circuits: From closed-system to open-system approaches
• Tunneling vortex dynamics in linearly coupled Bose-Hubbard rings
• Band gap structures for matter waves
• Quantum behaviour of open pumped and damped Bose-Hubbard trimers
• Mesoscopic dynamical differences from quantum state preparation in a Bose-Hubbard trimer
• Nonequilibrium Transport in a Superfluid Josephson Junction Chain: Is There Negative Differential Conductivity?