Improving quantum annealing of the ferromagnetic 
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-spin model through pausing

Passarelli, Gianluca; Cataudella, V.; Lucignano, P.

doi:10.1103/physrevb.100.024302

Cited by 48 publications

(34 citation statements)

References 77 publications

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“…with conventional quantum annealing, where the success probability exhibits a peak as a function of the pausing time, when the pause is inserted about 20 % later than s ∆ , and then rapidly returns to its baseline value [15,22]. In contrast, for s inv < s ∆ , the effect of the pause is negligible; the solid (with pause) and dotted (no pause) lines in Fig.…”

Section: Open System Dynamics With a Pausementioning

confidence: 91%

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Reverse quantum annealing of the p -spin model with relaxation

et al. 2020

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In reverse quantum annealing, the initial state is an eigenstate of the final problem Hamiltonian and the transverse field is cycled rather than strictly decreased as in standard (forward) quantum annealing. We present a numerical study of the reverse quantum annealing protocol applied to the p-spin model (p = 3), including pausing, in an open system setting accounting for dephasing in the energy eigenbasis, which results in thermal relaxation. We consider both independent and collective dephasing and demonstrate that in both cases the open system dynamics substantially enhances the performance of reverse annealing. Namely, including dephasing overcomes the failure of purely closed system reverse annealing to converge to the ground state of the p-spin model. We demonstrate that pausing further improves the success probability. The collective dephasing model leads to somewhat better performance than independent dephasing. The protocol we consider corresponds closely to the one implemented in the current generation of commercial quantum annealers, and our results help to explain why recent experiments demonstrated enhanced success probabilities under reverse annealing and pausing.

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Section: Open System Dynamics With a Pausementioning

confidence: 91%

“…Quantum annealing in the presence of a low temperature bath can benefit from pauses inserted at certain times during the dynamics [15,22]. During a pause, s(t) = constant, and the system evolves with a time independent Hamiltonian, subject to dephasing.…”

Section: Open System Dynamics With a Pausementioning

confidence: 99%

Reverse quantum annealing of the p -spin model with relaxation

et al. 2020

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“…Hence, the possibility of generating the dynamics induced by this kind of Hamiltonians exploiting realistic resources can give an interesting boost in the direction of quantum algorithm implementation. For this reason, several works have been dedicated in recent years to propose techniques to implement the ground states of the p-spin Hamiltonian, with a particular focus on techniques that involve shortcuts to adiabaticity [61][62][63][64][65][66][67][68] . The search for an optimal parent Hamiltonian can be considered a further contribution to the debate on this topic.…”

Section: B Time-dependent Ground State Of the P-spin Modelmentioning

confidence: 99%

Optimal parent Hamiltonians for time-dependent states

Rattacaso,

Passarelli,

Mezzacapo

et al. 2021

Preprint

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Given a generic time-dependent many-body quantum state, we determine the associated parent Hamiltonian. This procedure may require, in general, interactions of any sort. Enforcing the requirement of a fixed set of engineerable Hamiltonians, we find the optimal Hamiltonian once a set of realistic elementary interactions is defined. We provide three examples of this approach. We first apply the optimization protocol to the ground states of the one-dimensional Ising model and a ferromagnetic p-spin model but with time-dependent coefficients. We also consider a time-dependent state that interpolates between a product state and the ground state of a p-spin model. We determine the time-dependent optimal parent Hamiltonian for these states and analyze the capability of this Hamiltonian of generating the state evolution. Finally, we discuss the connections of our approach to shortcuts to adiabaticity.

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“…Developing quantum annealing processors that support improved qubit coherence times would allow greater functionality in computation. Higher precision flux control, afforded by improved coherence, is required by many computational problems of interest [36][37][38]. In general, just how much of a computational advantage greater qubit coherence provides in quantum annealing processes is itself an open scientific question [39,40].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of long-range correlations via susceptibility measurements in a one-dimensional superconducting Josephson spin chain

Tennant,

Dai,

Martinez

et al. 2021

Preprint

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Spin chains have long been considered an effective medium for long-range interactions, entanglement generation, and quantum state transfer. In this work, we explore the properties of a spin chain implemented with superconducting flux circuits, designed to act as a connectivity medium between two superconducting qubits. The susceptibility of the chain is probed and shown to support long-range, cross chain correlations. In addition, interactions between the two end qubits, mediated by the coupler chain, are demonstrated. This work has direct applicability in near term quantum annealing processors as a means of generating long-range, coherent coupling between qubits.

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Improving quantum annealing of the ferromagnetic p -spin model through pausing

Cited by 48 publications

References 77 publications

Reverse quantum annealing of the p -spin model with relaxation

Reverse quantum annealing of the p -spin model with relaxation

Optimal parent Hamiltonians for time-dependent states

Demonstration of long-range correlations via susceptibility measurements in a one-dimensional superconducting Josephson spin chain

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