Experimental decoherence mitigation using a weak measurement-based scheme and the duality quantum algorithm

TL;DR

This paper demonstrates an experimental scheme using weak measurement and the duality quantum algorithm on an NMR quantum processor to mitigate decoherence effects, effectively protecting quantum states in a four-qubit system.

Contribution

It introduces a novel implementation of non-unitary operations via the duality quantum algorithm for decoherence mitigation in quantum systems.

Findings

Successful state protection demonstrated on a four-qubit system

Effective mitigation of amplitude damping decoherence

Implementation of non-unitary operations using duality quantum algorithm

Abstract

We experimentally demonstrate a weak measurement and measurement reversal-based scheme to ameliorate the effects of decoherence due to amplitude damping, on an NMR quantum processor. The weak measurement and measurement reversal processes require the implementation of non-unitary operations, which are typically infeasible on conventional quantum processors, where only unitary quantum operations are allowed. The duality quantum algorithm is used to efficiently implement the required non-unitary quantum operations corresponding to weak measurement and measurement reversal. We experimentally validate the efficacy of the weak measurement-based decoherence mitigation scheme by showing state protection on a four-qubit system, with one qubit being designated as the 'system qubit', while the remaining three qubits serve as 'ancilla qubits'. Our experimental results clearly demonstrate the success of the weak measurement-based decoherence mitigation scheme in protecting the desired state. Since the measurement process involved has trace less than unity, the scheme can be thought of as a filtration scheme, where a subset of the spins is protected while the rest of the spins can be discarded.