Quantum Simulation of Open Quantum Systems Using a Unitary Decomposition of Operators

Schlimgen, Anthony W.; Head-Marsden, Kade; Sager, LeeAnn M.; Narang, Prineha; Mazziotti, David A.

doi:10.1103/physrevlett.127.270503

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Quantum Simulation of Open Quantum Systems Using a Unitary Decomposition of Operators

Schlimgen, Anthony W.·Head-Marsden, Kade·Sager, LeeAnn M.·Narang, Prineha·Mazziotti, David A.

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Abstract

Electron transport in realistic physical and chemical systems often involves the nontrivial exchange of energy with a large environment, requiring the definition and treatment of open quantum systems. Because the time evolution of an open quantum system employs a nonunitary operator, the simulation of open quantum systems presents a challenge for universal quantum computers constructed from only unitary operators or gates. Here, we present a general algorithm for implementing the action of any nonunitary operator on an arbitrary state on a quantum device. We show that any quantum operator can be exactly decomposed as a linear combination of at most four unitary operators. We demonstrate this method on a two-level system in both zero and finite temperature amplitude damping channels. Furthermore, the results are in agreement with classical calculations, showing promise in simulating nonunitary operations on intermediate-term and future quantum devices.

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74 ATOMIC AND MOLECULAR PHYSICS Atomic & molecular structure Many-body techniques Quantum computation Quantum simulation

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Schlimgen, Anthony W., Head-Marsden, Kade, Sager, LeeAnn M., Narang, Prineha, Mazziotti, David A.. 2021-12-29. Quantum Simulation of Open Quantum Systems Using a Unitary Decomposition of Operators. https://doi.org/10.1103/physrevlett.127.270503

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