Enhanced delegated computing using coherence

TL;DR

This paper demonstrates how coherence in quantum and classical systems can enable secure delegated classical computation with minimal resources, combining quantum and classical approaches.

Contribution

It introduces a novel method using coherence for secure delegated classical computation with limited client capabilities, supported by experimental implementation.

Findings

Client can perform universal classical computation with XOR gates using quantum coherence.

Secure delegated computation achieved with minimal quantum and classical resources.

Experimental setup with photonic qubits and coherent light validates the approach.

Abstract

A long-standing question is whether it is possible to delegate computational tasks securely. Recently, both a classical and a quantum solution to this problem were found. Here, we study the interplay of classical and quantum approaches and show how coherence can be used as a tool for secure delegated classical computation. We show that a client with limited computational capacity - restricted to an XOR gate - can perform universal classical computation by manipulating information carriers that may occupy superpositions of two states. Using single photonic qubits or coherent light, we experimentally implement secure delegated classical computations between an independent client and a server. The server has access to the light sources and measurement devices, whereas the client may use only a restricted set of passive optical devices to manipulate the light beams. Thus, our work highlights how minimal quantum and classical resources can be combined and exploited for classical computing.