Quantum Ratchets for Quantum Communication with Optical Superlattices

TL;DR

This paper introduces a quantum ratchet mechanism in optical superlattices to enable precise quantum information transport, leveraging modulation techniques and optimal control for potential quantum computing applications.

Contribution

It presents a novel method for quantum information transport using a modulated quantum ratchet in optical lattices, including analysis of interactions and experimental feasibility.

Findings

Quantum ratchet enables directed atomic transport without net force.

Perfect qubit and entangled state transfer along the lattice.

Feasibility discussed for current experimental setups.

Abstract

We propose to use a quantum ratchet to transport quantum information in a chain of atoms trapped in an optical superlattice. The quantum ratchet is created by a continuous modulation of the optical superlattice which is periodic in time and in space. Though there is zero average force acting on the atoms, we show that indeed the ratchet effect permits atoms on even and odd sites to move along opposite directions. By loading the optical lattice with two-level bosonic atoms, this scheme permits to perfectly transport a qubit or entangled state imprinted in one or more atoms to any desired position in the lattice. From the quantum computation point of view, the transport is achieved by a smooth concatenation of perfect swap gates. We analyze setups with noninteracting and interacting particles and in the latter case we use the tools of optimal control to design optimal modulations. We also discuss the feasibility of this method in current experiments.