Non-adiabatic many-atom quantum state control in few-well systems

TL;DR

This paper introduces a rapid, non-adiabatic control scheme for manipulating many-atom quantum states in double-well systems, enabling high-fidelity operations like state transfer, entanglement, and quantum gates.

Contribution

It develops a discrete control method using energy level shifts and optimized sequences to achieve full controllability of interacting bosons in realistic settings.

Findings

Achieves high-fidelity non-adiabatic population transfer

Demonstrates creation of N00N-states and quantum gates

Extends controllability to a wide range of interaction parameters

Abstract

We present a fast scheme for arbitrary unitary control of interacting bosonic atoms in a double-well. Assuming fixed inter-well tunnelling rate and intra-well interaction strength, we control the many-atom state by a discrete sequence of shifts of the single-well energies. For strong interactions, resonant tunnelling transitions implement beam-splitter U(2) rotations among atom number eigenstates, which can be combined and, thus, permit full controllability. By numerically optimizing such sequences of couplings at avoided level crossings (CALC), we extend the realm of full controllability to a wide range of realistic interaction parameters, while we remain in the simple control space. We demonstrate the efficiency and the high achievable fidelity of our proposal with non-adiabatic population transfer, N00N-state creation, a C-NOT gate, and a transistor-like, conditional evolution of several atoms.