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Related papers: Phase sensing beyond the standard quantum limit wi…

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Nonlinear quantum metrology schemes can lead to faster than Heisenberg limited scalings for the measurement uncertainty. We study a Michelson interferometer embedded in a Kerr medium [Luis and Rivas, Phys. Rev. A 92, 022104 (2015)] that…

Quantum Physics · Physics 2021-12-07 Bijoy John Mathew , Anil Shaji

We cast the phase state as a $SU(1,1)$ nonlinear coherent state to support the idea that the $SU(1,1)$ representation of the electromagnetic field may be helpful in some instances and to bring forward that it may relate to the phase state…

Quantum Physics · Physics 2014-06-05 F. Soto-Eguibar , B. M. Rodríguez-Lara , H. M. Moya-Cessa

We consider an interferometer that contains active elements, such as a parametric amplifier, with general two-mode Gaussian unitary channels rather than the usually considered phase-shift channel. We concentrate on a scheme based on the…

Quantum Physics · Physics 2019-03-11 Richard Howl , Ivette Fuentes

Bright squeezed vacuum, a promising tool for quantum information, can be generated by high-gain parametric down-conversion. However, its frequency and angular spectra are typically quite broad, which is undesirable for applications…

We study non-Abelian fractional quantum Hall state in double layer systems at total filling factor $1/2$. Recent progresses in two-dimensional van der Waals materials made it possible to explore the regime with very small interlayer…

Strongly Correlated Electrons · Physics 2025-02-24 Xiang-Jian Hou , Lei Wang , Ying-Hai Wu

We present an efficient and robust protocol for quantum-enhanced sensing using a single qubit in the topological waveguide system. Our method relies on the topological-paired bound states, which are localized near the qubit and can be…

Quantum Physics · Physics 2025-08-08 Tao Zhang , Peng Xu , Jiazhong Hu , Xingze Qiu

Quantum-enhanced phase estimation paves the way to ultra-precision sensing and is of great realistic significance. In this paper we investigate theoretically the estimation of a second-order nonlinear phase shift using a coherent state and…

Quantum Physics · Physics 2019-02-13 Jian-Dong Zhang , Zi-Jing Zhang , Long-Zhu Cen , Jun-Yan Hu , Yuan Zhao

Distributed quantum sensing exploits entanglement to enhance the estimation of multiple parameters across a network of spatially-separated sensors, achieving sensitivities beyond the classical limit. Potential applications cover a plethora…

We report a direct demonstration of quantum-enhanced sensing in the Fourier domain by comparing single- and two-photon interference in a fiber-based interferometer under strictly identical noise conditions. The simultaneous acquisition of…

The fundamental quantum interferometry bound limits the sensitivity of an interferometer for a given total rate of photons and for a given decoherence rate inside the measurement device.We theoretically show that the recently reported…

Quantum Physics · Physics 2013-10-15 Rafal Demkowicz-Dobrzanski , Konrad Banaszek , Roman Schnabel

Quantum coherence is critical resource for applications in quantum technology, among which quantum-enhanced sensing represents a typical example.Compared with quantum metrology with entangled states of multiple qubits, bosonic…

Quantum Physics · Physics 2025-04-01 Xiao-Wei Zheng , Jun-Cong Zheng , Xue-Feng Pan , Pengbo Li

We theoretically studied the quantum Cram\'{e}r-Rao bound of an actively correlated Mach-Zehnder interferometer (ACMZI), where the quantum Fisher information obtained by the phase-averaging method can give the proper phase-sensing limit…

Quantum Physics · Physics 2021-08-04 Qiang Wang , Gao-Feng Jiao , Zhifei Yu , L. Q. Chen , Weiping Zhang , Chun-Hua Yuan

Quantum states with sub-Planck features exhibit sensitivity to phase-space displacements beyond the standard quantum limit, making them useful for quantum metrology. In the context of the SU(1,1) group, sub-Planck features have been…

Quantum Physics · Physics 2026-02-17 Naeem Akhtar , Jia-Xin Peng , Tariq Aziz , Xiaosen Yang , Dong Wang

Entanglement, a key feature of quantum mechanics, is a resource that allows the improvement of precision measurements beyond the conventional bound reachable by classical means. This is known as the standard quantum limit, already defining…

Other Condensed Matter · Physics 2008-12-09 J. Esteve , C. Gross , A. Weller , S. Giovanazzi , M. K. Oberthaler

We compare the energies of different electron solids, such as bubble crystals with triangular and square symmetry and stripe phases, to those of correlated quantum liquids in partially filled intermediate Landau levels. Multiple transitions…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. O. Goerbig , P. Lederer , C. Morais Smith

We show that the phase sensitivity $\Delta \theta$ of a Mach-Zehnder interferometer fed by a coherent state in one input port and squeezed-vacuum in the other one is i) independent from the true value of the phase shift and ii) can reach…

Quantum Physics · Physics 2009-11-13 L. Pezze' , A. Smerzi

Path-entangled multi-photon states allow optical phase-sensing beyond the shot-noise limit, provided that an efficient parity measurement can be implemented. Realising this experimentally is technologically demanding, as it requires…

Interference experiments provide a simple yet powerful tool to unravel fundamental features of quantum physics. Here we engineer an RF-driven, time-dependent bilinear coupling that can be tuned to implement a robust 50:50 beamsplitter…

Second order quantum phase transitions, with well-known features such as long-range entanglement, symmetry breaking, and gap closing, exhibit quantum enhancement for sensing at criticality. However, it is unclear which of these features are…

Quantum Physics · Physics 2022-08-29 Saubhik Sarkar , Chiranjib Mukhopadhyay , Abhijeet Alase , Abolfazl Bayat

Matter-wave interferometer of ultracold atoms with different linear momenta has been extensively studied in theory and experiment. The vortex matter-wave interferometer with different angular momenta is applicable as a quantum sensor for…

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