Collective Spin-Light and Light-Mediated Spin-Spin Interactions in an Optical Cavity by Zeyang Li, Boris Braverman, Simone Colombo, Chi Shu, Akio Kawasaki, Albert F. Adiyatullin, Edwin Pedrozo-Peñafiel, Enrique Mendez, Vladan Vuletić

“…We present analytical expressions for the entanglement induced by the interaction, and determine the conditions that maximize the entanglement-induced gain over the standard quantum limit in quantum sensors and atomic clocks.…”
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Phase-controlled coherent photons for the quantum correlations in a delayed-choice quantum eraser scheme by Byoung S. Ham

“…Super-resolution has been studied over decades for quantum sensing to overcome the standard quantum limit. For the super-resolution, either quantum features of higher-order entangled photon pairs or classical features of phase-controlled coherent photons have been successfully demonstrated. …”
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Quantum state discrimination on reconfigurable noise-robust quantum networks by Nicola Dalla Pozza, Filippo Caruso

“…Numerical simulations show that after a transient time the probability of correct decision approaches the theoretical optimal quantum limit. These results are confirmed analytically for small graphs. …”
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Variational quantum metrology for multiparameter estimation under dephasing noise by Trung Kien Le, Hung Q. Nguyen, Le Bin Ho

“…Indeed, we demonstrate its ability to simultaneously estimate all parameters and surpass the standard quantum limit, making it a powerful tool for metrological applications.…”
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Magnetoresistance of vertical transport in InAs/GaSb superlattices by Broadley, V, Nicholas, R, Mason, N

“…We attribute the first peak to Esaki-Tsu miniband conduction and the repeat feature to LO-phonon-assisted miniband tunnelling, At high magnetic fields, in the quantum limit we observe a series of conductance peaks that satisfy the Stark-cyclotron-resonance condition. …”

Squeezed lasing by Jaksch, DH, Sánchez Muñoz, C

“…The squeezed laser can find applications that go beyond those of standard lasers thanks to the squeezed character, such as the direct application in Michelson interferometry beyond the standard quantum limit, or its use in atomic metrology.…”

The effect of the cross-gap alignment on magneto-transport in short period InAs/GaSb superlattices by Hales, V, Nicholas, R, Mason, N

“…At higher biases the superlattice exhibits a large magneto-resistance and in the quantum limit we observe conduction peaks, which satisfy the Stark-cyclotron-resonance condition. …”

Mass enhancement and electron-hole coupling in InAs/GaSb bilayers studied by cyclotron resonance by Petchsingh, C, Nicholas, R, Takashina, K, Mason, N, Zeman, J

“…At very high fields, in the quantum limit a new series of couplings is observed, with the resonances being split by energies in the range of 3-12 meV. …”

Sequential path entanglement for quantum metrology. by Jin, X, Peng, C, Deng, Y, Barbieri, M, Nunn, J, Walmsley, I

“…Using path-entangled states, the standard quantum limit can be beaten, and the Heisenberg limit can be achieved. …”

Fundamental constraints on particle tracking with optical tweezers by Michael A Taylor, Joachim Knittel, Warwick P Bowen

“…A general quantum limit to the sensitivity of particle position measurements is derived following the simple principle of the Heisenberg microscope. …”
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Motional Fock states for quantum-enhanced amplitude and phase measurements with trapped ions by Fabian Wolf, Chunyan Shi, Jan C. Heip, Manuel Gessner, Luca Pezzè, Augusto Smerzi, Marius Schulte, Klemens Hammerer, Piet O. Schmidt

“…Quantum metrology allows surpassing the standard quantum limit, but methods relying on squeezing require to know the orientation of the squeezed quadrature with respect to the signal. …”
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Classical and Quantum Surface Plasmon Resonance Biosensing by K. T. Mpofu, S. Ombinda-Lemboumba, P. Mthunzi-Kufa

“…We will review recent experimental and theoretical work showing that making use of quantum states of light offers a great enhancement in the precision of our biosensor, as they can go below the shot-noise limit (standard quantum limit) of precision in intensity noise detection. …”
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Quantum noise and its evasion in feedback oscillators by Hudson A. Loughlin, Vivishek Sudhir

“…Our analysis clarifies the quantum limits to the stability of feedback oscillators in general, derives a standard quantum limit (SQL) for all such devices, and quantifies the efficacy of quantum strategies in realizing sub-SQL oscillators.…”
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Emptying Dirac valleys in bismuth using high magnetic fields by Zengwei Zhu, Jinhua Wang, Huakun Zuo, Benoît Fauqué, Ross D. McDonald, Yuki Fuseya, Kamran Behnia

“…Materials in large magnetic fields can be driven into the quantum limit, where electrons occupy only the lowest Landau level and the response is determined by interactions. …”
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Quantum metrology with Dicke squeezed states by Z Zhang, L M Duan

“…We introduce a new class of quantum many-particle entangled states, called the Dicke squeezed (or DS) states, which can be used to improve the precision in quantum metrology beyond the standard quantum limit. We show that the enhancement in measurement precision is characterized by a single experimentally detectable parameter, called the Dicke squeezing ${{\xi }_{D}}$ , which also bounds the entanglement depth for this class of states. …”
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Fast high-fidelity geometric quantum control with quantum brachistochrones by Yang Dong, Ce Feng, Yu Zheng, Xiang-Dong Chen, Guang-Can Guo, Fang-Wen Sun

“…With the fast and high-fidelity universal set of geometric gates available, we implement a quantum entanglement-enhanced phase estimation algorithm and demonstrate the Heisenberg quantum limit of phase estimation at room temperature. …”
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Superconducting nanowire single-photon detectors for quantum information by You Lixing

“…The superconducting nanowire single-photon detector (SNSPD) is a quantum-limit superconducting optical detector based on the Cooper-pair breaking effect by a single photon, which exhibits a higher detection efficiency, lower dark count rate, higher counting rate, and lower timing jitter when compared with those exhibited by its counterparts. …”
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Quantum metrology with imperfect states and detectors by Datta, A, Zhang, L, Thomas-Peter, N, Dorner, U, Smith, B, Walmsley, I

“…The second of these has received much attention; we show that it is the least damaging to surpassing the standard quantum limit in a optical interferometric sensor. Further, we show that photonic states that can be prepared in the laboratory using feasible resources allow a measurement strategy using photon-number-resolving detectors that not only attains the Heisenberg limit for phase estimation in the absence of losses, but also deliver close to the maximum possible precision in realistic scenarios including losses and inefficiencies. …”

Joint estimation of phase and phase diffusion for quantum metrology. by Vidrighin, MD, Donati, G, Genoni, MG, Jin, X, Kolthammer, W, Kim, MS, Datta, A, Barbieri, M, Walmsley, I

“…Here we investigate the joint estimation of a phase shift and the amplitude of phase diffusion at the quantum limit. For several relevant instances, this multiparameter estimation problem can be effectively reshaped as a two-dimensional Hilbert space model, encompassing the description of an interferometer phase probed with relevant quantum states--split single-photons, coherent states or N00N states. …”

Quantum phase estimation with lossy interferometers by Demkowicz-Dobrzanski, R, Dorner, U, Smith, B, Lundeen, J, Wasilewski, W, Banaszek, K, Walmsley, I

“…The corresponding optimal precision, i.e., the lowest possible uncertainty, is shown to beat the standard quantum limit thus outperforming classical interferometry. …”