Signatures of Open and Noisy Quantum Systems in Single-Qubit Quantum Annealing

Morrell, Zachary; Vuffray, Marc; Lokhov, Andrey Y.; Baertschi, Andreas; Albash, Tameem; Coffrin, Carleton

doi:10.2172/1883115

Cited by 2 publications

(2 citation statements)

References 52 publications

(65 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The h-gain feature of D-Wave quantum annealers has been used before in a variety of contexts [12,43,60,95,96]. The h-gain feature could also be used for other interesting simulation methods such as implementing adiabatic reverse annealing [97,98].…”

Section: State Encoding Methodsmentioning

confidence: 99%

Mapping State Transition Susceptibility in Quantum Annealing

Pelofske¹

2022

Preprint

View full text Add to dashboard Cite

Quantum annealing is a novel type of analog computation that aims to use quantum mechanical fluctuations to search for optimal solutions of Ising problems. Quantum annealing in the transverse field Ising model, implemented on D-Wave devices, works by applying a time dependent transverse field, which puts all qubits into a uniform state of superposition, and then applying a Hamiltonian over time which describes a user programmed Ising problem. We present a method which utilizes two control features of D-Wave quantum annealers, reverse annealing and an h-gain schedule, to quantify the susceptibility, or the distance, between two classical states of an Ising problem. The starting state is encoded using reverse annealing, and the second state is encoded on the linear terms of problem Hamiltonian. An h-gain schedule is specified which incrementally increases the strength of the linear terms, thus allowing a quantification of the h-gain strength required to transition the anneal into a specific state at the final measurement. By the nature of quantum annealing, the state tends towards global minima and therefore we restrict the second classical state to a minimum solution of the given Ising problem. This susceptibility mapping, when enumerated across all initial states, shows in detail the behavior of the quantum annealer during reverse annealing. The procedure is experimentally demonstrated on three small test Ising's which were embedded in parallel on the D-Wave Advantage system4.1. Analysis of the state transition mapping shows detailed characteristics of the reverse annealing process including intermediate state transition paths, which are visually represented as state transition networks.

show abstract

Section: State Encoding Methodsmentioning

confidence: 99%

Mapping State Transition Susceptibility in Quantum Annealing

Pelofske¹

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…There is considerable interest in the potential of D-Wave machines to exploit quantum properties, and recent experiments with a D-Wave machine have shown good agreement with theoretical predictions based on the Schrodinger dynamics [20,21]. To this end, a study has attempted to use longitudinal magnetic fields to probe the dynamics of a qubit and distinguish the effects of noise in the D-Wave machine [22]. Tunneling spectroscopy [23] is a way to estimate the energy gap of the transverse-field Ising Hamiltonian, and numerical simulations of open quantum systems have been performed to reproduce the results of the tunneling spectroscopy by using the D-wave machine [24].…”

Section: Introductionmentioning

confidence: 99%

Measurement of the incoherent decay rate of quantum states in quantum annealing with a D-Wave machine

Imoto,

Susa,

Kadowaki

et al. 2024

Preprint

View full text Add to dashboard Cite

Quantum annealing has been demonstrated with superconducting qubits. Such a quantum annealer has been used to solve combinational optimization problems. Moreover, it serves as a quantum simulator for investigating the properties of the quantum many-body systems. However, the coherence properties of actual devices provided by D-Wave Quantum Inc. have not been explored sufficiently. Here, we measure the energy relaxation of the excited state in quantum annealing with the D-Wave device. Specifically, we investigate the incoherent decay rate of the first excited states of a fully connected Ising model with a transverse field. We find that the decay rate of the excited states of the model is orders of magnitude smaller than that of the excited state of a single qubit, and we qualitatively explain this phenomenon by using theoretical methods. Since our numerical simulations show that the first excited state during QA for the model is entangled, our experimental results indicate that the long-lived entangled state can be generated during QA with the D-Wave machine.

show abstract

Signatures of Open and Noisy Quantum Systems in Single-Qubit Quantum Annealing

Cited by 2 publications

References 52 publications

Mapping State Transition Susceptibility in Quantum Annealing

Mapping State Transition Susceptibility in Quantum Annealing

Measurement of the incoherent decay rate of quantum states in quantum annealing with a D-Wave machine

Contact Info

Product

Resources

About