Remotely Controlled Entanglement Generation

TL;DR

This paper introduces a method for generating and controlling entanglement in multi-qubit systems using a locally controlled auxiliary system, eliminating the need for switching interactions on and off, and enhancing error tolerance.

Contribution

It presents a novel approach for quantum control by mediating entanglement through an auxiliary system with always-on interactions, avoiding the need for dynamic interaction switching.

Findings

Enables selective entanglement generation by changing the auxiliary system's state.

Provides an alternative quantum control method without switching interactions.

Offers increased error tolerance to position fluctuations.

Abstract

We consider a system of multiple qubits without any quantum control. We show that one can mediate entanglement between different subsystems in a controlled way by adding a (locally) controlled auxiliary system of the same size that couples via an always-on, distant dependent interaction to the system qubits. Solely by changing the internal state of the control system, one can selectively couple it to selected qubits, and ultimately generate different kinds of entanglement within the system. This provides an alternative way for quantum control and quantum gates that does not rely on the ability to switch interactions on and off at will, and can serve as a locally controlled quantum switch where all entanglement patterns can be created. We demonstrate that such an approach also offers an increased error tolerance w.r.t. position fluctuations.