Thermal Equilibrium as an Initial State for Quantum Computation by NMR

TL;DR

This paper introduces a method for quantum computation using NMR that leverages thermal equilibrium states, eliminating the need for pseudopure states and enabling scalable quantum algorithms with clear experimental results.

Contribution

It demonstrates a novel approach to NMR quantum computing by using thermal equilibrium states, simplifying state preparation and maintaining signal strength for larger qubit systems.

Findings

Successful implementation of Deutsch-Jozsa algorithm with four qubits

Thermal equilibrium states enable scalable NMR quantum computation

Clear spectral distinction between constant and balanced functions

Abstract

We present a method of using a nuclear magnetic resonance computer to solve the Deutsch-Jozsa problem in which: (1) the number of molecules in the NMR sample is irrelevant to the number of qubits available to an NMR quantum computer, and (2) the initial state is chosen to be the state of thermal equilibrium, thereby avoiding the preparation of pseudopure states and the resulting exponential loss of signal as the number of qubits increases. The algorithm is described along with its experimental implementation using four active qubits. As expected, measured spectra demonstrate a clear distinction between constant and balanced functions.