Exponential precision by reaching a quantum critical point

Garbe, Louis; Abah, Obinna; Felicetti, Simone; Puebla, Ricardo

doi:10.48550/arxiv.2112.11264

Cited by 5 publications

(8 citation statements)

References 70 publications

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“…Critical quantum sensors can then also be implemented with controllable small-scale quantum devices, without requiring the control of complex many-body systems. These results have prompted an intense research effort dedicated to designing efficient protocols [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] in terms of high estimation precision and limited measurement time, and which can be implemented with experimentally feasible operations. Practical applications in quantum magnetometry and superconducting-qubit readout were also been proposed [ 52 ].…”

Section: Introductionmentioning

confidence: 99%

Critical Quantum Metrology in the Non-Linear Quantum Rabi Model

Ying

Felicetti

Liu

et al. 2022

Entropy

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The quantum Rabi model (QRM) with linear coupling between light mode and qubit exhibits the analog of a second-order phase transition for vanishing mode frequency which allows for criticality-enhanced quantum metrology in a few-body system. We show that the QRM including a nonlinear coupling term exhibits much higher measurement precisions due to its first-order-like phase transition at finite frequency, avoiding the detrimental slowing-down effect close to the critical point of the linear QRM. When a bias term is added to the Hamiltonian, the system can be used as a fluxmeter or magnetometer if implemented in circuit QED platforms.

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Section: Introductionmentioning

confidence: 99%

Critical Quantum Metrology in the Non-Linear Quantum Rabi Model

Ying

Felicetti

Liu

et al. 2022

Entropy

Self Cite

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“…On the other hand, the milestone work of Braak revealing the integrability [3] of DOI: 10.1002/qute.202200068 the quantum Rabi model (QRM), [17] which is a most fundamental model of light-interactions, has triggered an intensive dialogue between mathematics and physics [18] and leads to a boom of theoretical developments. [4,5, Without mentioning the ubiquitous role of lightmatter interaction and its broad relevance to quantum optics, quantum information and quantum computation, [1,[64][65][66][67] quantum metrology, [36][37][38]68] condensed matter, [2,27,28] and relativistic systems, [69] the explosively-growing investigations have yielded abundant findings in the QRM and its extensions, such as hidden symmetry, [60][61][62][63] various patterns of symmetry breaking, [26,27,29] few-body quantum phase transitions, [5,[22][23][24][25][26][27][28][29]70] multicriticalities and multiple points, [26][27][28] universality classification, [24,25,27,52] spectral collapse, [33]…”

Section: Introductionmentioning

confidence: 99%

Scaling Relations and Topological Quadruple Points in Light‐Matter Interactions with Anisotropy and Nonlinear Stark Coupling

Ying

2022

Adv Quantum Tech

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Universality is a common quality in different physical parameters that is rooted in the deep nature of physical systems. Scaling relation is a typical universality for critical phenomena around a quantum phase transition, while topological classification provides another type of universality essentially different from the critical universality. Both classes of universalities can be present in a single-qubit system with light-matter interactions, as exhibiting generally in the fundamental quantum Rabi model with anisotropy not only for linear coupling but also for nonlinear Stark coupling (NSC). In low frequencies different levels of scaling relations are extracted, holding for anisotropic or/and NSCs, locally or globally. At finite frequencies such a critical universality breaks down and diversity is dominant. However, common topological feature of the ground state can be extracted from the node number, which yields a topological class of universality amidst the critical diversity. Both conventional and unconventional topological transitions emerge, with their meeting, which never occurs in linear interaction, enabled by the nonlinear coupling to form topological quadruple points which are found to be spin-invariant points. Sensitivity analysis indicates that the NSC can be another applicable approach to manipulate topological transitions in addition to coupling anisotropy.

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“…For any resource T (e.g., time [34][35][36][37] or number of particles [38][39][40]), Fisher information, in general, scales as F ∼ T η . While classical sensors at best result in η ¼ 1 (standard limit), quantum sensors can achieve an enhanced sensitivity with η ¼ 2 (Heisenberg limit) [38][39][40] or even η > 2 (super-Heisenberg limit) [41]. A fundamental open problem is to determine which quantum features can be exploited to achieve quantumenhanced sensing.…”

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confidence: 99%

Sequential Measurements for Quantum-Enhanced Magnetometry in Spin Chain Probes

et al. 2022

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Quantum sensors outperform their classical counterparts in their estimation precision, given the same amount of resources. So far, quantum-enhanced sensitivity has been achieved by exploiting the superposition principle. This enhancement has been obtained for particular forms of entangled states, adaptive measurement basis change, critical many-body systems, and steady state of periodically driven systems. Here, we introduce a different approach to obtain quantum-enhanced sensitivity in a many-body probe through utilizing the nature of quantum measurement and its subsequent wave function collapse without demanding prior entanglement. Our protocol consists of a sequence of local measurements, without reinitialization, performed regularly during the evolution of a many-body probe. As the number of sequences increases, the sensing precision is enhanced beyond the standard limit, reaching the Heisenberg bound asymptotically. The benefits of the protocol are multifold as it uses a product initial state and avoids complex initialization (e.g., prior entangled states or critical ground states) and allows for remote quantum sensing.

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Exponential precision by reaching a quantum critical point

Cited by 5 publications

References 70 publications

Critical Quantum Metrology in the Non-Linear Quantum Rabi Model

Critical Quantum Metrology in the Non-Linear Quantum Rabi Model

Scaling Relations and Topological Quadruple Points in Light‐Matter Interactions with Anisotropy and Nonlinear Stark Coupling

Sequential Measurements for Quantum-Enhanced Magnetometry in Spin Chain Probes

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