Ancilla-Driven Universal Quantum Computation

TL;DR

This paper introduces an ancilla-driven approach for universal quantum computation, enabling remote manipulation of quantum registers through a single ancilla and fixed interactions, simplifying experimental implementation.

Contribution

It characterizes all suitable interactions that allow universal quantum operations via ancilla-driven measurements, advancing quantum control methods.

Findings

Identifies all interactions E that enable deterministic quantum operations.

Demonstrates the scheme's advantages in state preparation and measurement without direct register control.

Provides a framework for experimental realization of quantum computation.

Abstract

We propose a method of manipulating a quantum register remotely with the help of a single ancilla that steers the evolution of the register. The fully controlled ancilla qubit is coupled to the computational register solely via a fixed unitary two-qubit interaction, E, and then measured in suitable bases. We characterize all interactions E that induce a unitary, step-wise deterministic measurement back-action on the register sufficient to implement any arbitrary quantum channel. Our scheme offers significant experimental advantages for implementing computations, preparing states and performing generalized measurements as no direct control of the register is required.