Fast macroscopic-superposition-state generation by coherent driving

Yukawa, Emi; Milburn, G. J.; Nemoto, Kae

doi:10.1103/physreva.97.013820

Cited by 7 publications

(15 citation statements)

References 67 publications

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“…This happens because of the exponentially small energy gap between the ground state and the first excited state. Adiabatic generation is one of the strategies to create this cat state [23,26,27].…”

Section: A Bosonic Josephson Junctionsmentioning

confidence: 99%

“…The key point of adiabatic generation is the parity conservation [27] ensured by the commutation relation…”

Section: A Bosonic Josephson Junctionsmentioning

confidence: 99%

“…Note that it is difficult to directly approach these ground states by just cooling down because of small energy gaps. In adiabatic generation, we first prepare the trivial ground state in the large Rabi coupling limit, and then we adiabatically sweep parameters into the large one-axis twisting interaction limit [23][24][25][26][27]. Notably generation time of a cat state is comparable to typical coherence time [27].…”

Section: Introductionmentioning

confidence: 99%

“…In adiabatic generation, we first prepare the trivial ground state in the large Rabi coupling limit, and then we adiabatically sweep parameters into the large one-axis twisting interaction limit [23][24][25][26][27]. Notably generation time of a cat state is comparable to typical coherence time [27]. However, the size of generated cat states is still up to N = 20 [16].…”

Section: Introductionmentioning

confidence: 99%

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Suppressing nonadiabatic transitions during adiabatic generation of highly entangled states in bosonic Josephson junctions

Hatomura

2019

Phys. Rev. A

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We study suppression of nonadiabatic transitions during adiabatic generation of a cat-like state (a superposition of different size cat states) and a spin squeezed state in a bosonic Josephson junction. In order to minimize the adiabatic error, we use quantum adiabatic brachistochrone, which enables us to track a geometrically efficient path in parameter space under given conditions without requiring additional terms. For creation of a cat-like state, divergence of the quantum geometric tensor associated with gap closing at the critical point is avoided because of the parity conservation. The resulting schedules of parameters are smooth and monotonically decreasing curves. Use of these schedules offers reduction of time to generate both of a cat-like state and a spin squeezed state.

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Section: A Bosonic Josephson Junctionsmentioning

confidence: 99%

“…The key point of adiabatic generation is the parity conservation [27] ensured by the commutation relation…”

Section: A Bosonic Josephson Junctionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Suppressing nonadiabatic transitions during adiabatic generation of highly entangled states in bosonic Josephson junctions

Hatomura

2019

Phys. Rev. A

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“…They have been mostly created by Hamiltonians with many-body interactions, which entangles the qubits to achieve the HL for magnetic field sensing. Moreover, specific types of the spin squeezed Hamiltonians provide us with entangled states [9,11,[15][16][17][18][19][20] that also achieve the HL sensitivity. However, the spin squeezed Hamiltonians typically contain many-body interactions such as long-range interactions between the probe qubits, and realizing such interactions is challenging for some physical systems.…”

Section: Introductionmentioning

confidence: 99%

Entanglement-enhanced sensing using a chain of qubits with always-on nearest-neighbor interactions

Yoshinaga,

Tatsuta,

Matsuzaki

2021

Preprint

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Quantum metrology is the use of genuinely quantum properties such as entanglement as a resource to outperform classical sensing strategies. Typically, entanglement is created by implementing gate operations or inducing many-body interactions. However, existing sensing schemes with these approaches require accurate control of the probe system such as switching on/off the interaction among qubits, which can be challenging for practical applications. Here, we propose an entanglement-enhanced sensing scheme with an always-on nearestneighbor interaction between qubits. We adopt the transverse field Ising chain as the probe system, and make use of the so-called "quantum domino" dynamics for the generation of the entangled states. In addition to the advantage that our scheme can be implemented without controlling the interactions, it only requires initialization of the system, projective measurements on a single qubit, and control of the uniform magnetic fields. We can achieve an improved sensitivity beyond the standard quantum limit even under the effect of realistic decoherence.

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Quantum metrology based on symmetry-protected adiabatic transformation: imperfection, finite time duration, and dephasing

Hatomura

Yoshinaga²,

Matsuzaki³

et al. 2022

New J. Phys.

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The aim of quantum metrology is to estimate target parameters as precisely as possible. In this paper, we consider quantum metrology based on symmetry-protected adiabatic transformation. We introduce a ferromagnetic Ising model with a transverse field as a probe and consider the estimation of a longitudinal field. Without the transverse field, the ground state of the probe is given by the Greenberger-Horne-Zeilinger state, and thus the Heisenberg limit estimation of the longitudinal field can be achieved through parity measurement. In our scheme, full information of the longitudinal field encoded on parity is exactly mapped to global magnetization by symmetry-protected adiabatic transformation, and thus the parity measurement can be replaced with global magnetization measurement. Moreover, this scheme requires neither accurate control of individual qubits nor that of interaction strength. We discuss the effects of the finite transverse field and nonadiabatic transitions as imperfection of adiabatic transformation. By taking into account finite time duration for state preparation, sensing, and readout, we also compare performance of the present scheme with a classical scheme in the absence and presence of dephasing.

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Fast macroscopic-superposition-state generation by coherent driving

Cited by 7 publications

References 67 publications

Suppressing nonadiabatic transitions during adiabatic generation of highly entangled states in bosonic Josephson junctions

Suppressing nonadiabatic transitions during adiabatic generation of highly entangled states in bosonic Josephson junctions

Entanglement-enhanced sensing using a chain of qubits with always-on nearest-neighbor interactions

Quantum metrology based on symmetry-protected adiabatic transformation: imperfection, finite time duration, and dephasing

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