Accelerated creation of NOON states with ultracold atoms via counterdiabatic driving

TL;DR

This paper proposes a counterdiabatic driving protocol to efficiently create NOON states with ultracold atoms, significantly reducing preparation time while maintaining high fidelity, which is crucial for quantum technologies.

Contribution

It introduces a feasible static parameter adaptation method for fast NOON state creation using counterdiabatic driving in ultracold gases, overcoming spectral gap limitations.

Findings

Protocol speed increases exponentially with atom number.

Achieves high fidelity in NOON state preparation.

Demonstrates practical implementation with ultracold quantum gases.

Abstract

A quantum control protocol is proposed for the creation of NOON states with $N$ ultracold bosonic atoms on two modes, corresponding to the coherent superposition $\vert N,0\rangle + \vert 0,N\rangle$. This state can be prepared by using a third mode where all bosons are initially placed and which is symmetrically coupled to the two other modes. Tuning the energy of this third mode across the energy level of the other modes allows the adiabatic creation of the NOON state. While this process normally takes too much time to be of practical usefulness, due to the smallness of the involved spectral gap, it can be drastically boosted through counterdiabatic driving which allows for efficient gap engineering. We demonstrate that this process can be implemented in terms of static parameter adaptations that are experimentally feasible with ultracold quantum gases. Gain factors in the required protocol speed are obtained that increase exponentially with the number of involved atoms and thus counterbalance the exponentially slow collective tunneling process underlying this adiabatic transition. Besides optimizing the protocol speed, our NOON state preparation scheme achieves excellent fidelities that are competitive for practical applications.