Optimal circular dichroism sensing with quantum light : multi-parameter estimation approach by Ioannou, Christina, Nair, Ranjith, Fernandez-Corbaton, Ivan, Gu, Mile, Rockstuhl, Carsten, Lee, Changhyoup

“…We show that the ultimate quantum limit can be achieved by various optimal schemes. …”
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Quantum Hair on Colliding Black Holes by Lawrence Crowell, Christian Corda

“…Black hole (BH) collisions produce gravitational radiation which is generally thought, in a quantum limit, to be gravitons. The stretched horizon of a black hole contains quantum information, or a form of quantum hair, which is a coalescence of black holes participating in the generation of gravitons. …”
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A robust quantum receiver for phase shift keyed signals by C R Müller, Ch Marquardt

“…Our scheme outperforms the standard quantum limit and approaches the Helstrom bound for any signal power. …”
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Experimental multiparameter quantum metrology in adaptive regime by Mauro Valeri, Valeria Cimini, Simone Piacentini, Francesco Ceccarelli, Emanuele Polino, Francesco Hoch, Gabriele Bizzarri, Giacomo Corrielli, Nicolò Spagnolo, Roberto Osellame, Fabio Sciarrino

“…Here, we combine on the same platform quantum-enhanced multiparameter estimation attaining the corresponding quantum limit and adaptive techniques. We demonstrate the simultaneous estimation of three optical phases in a programmable integrated photonic circuit, in the limited-resource regime. …”
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Dissipative Superradiant Spin Amplifier for Enhanced Quantum Sensing by Martin Koppenhöfer, Peter Groszkowski, Hoi-Kwan Lau, A.A. Clerk

“…We show that our approach can allow a system with a highly imperfect spin readout to approach standard-quantum-limit-like scaling in N within a factor of 2, without needing to change the actual readout mechanism. …”
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Suppressing Recoil Heating in Levitated Optomechanics Using Squeezed Light by C. Gonzalez-Ballestero, J.A. Zielińska, M. Rossi, A. Militaru, M. Frimmer, L. Novotny, P. Maurer, O. Romero-Isart

“…Moreover, we analyze the trade-off between measurement imprecision and back-action noise and show that optical detection beyond the standard quantum limit can be achieved. We predict that, with state-of-the-art squeezed light sources, laser recoil heating can be reduced by at least 60% by squeezing a single Gaussian mode with an appropriate incidence direction, and by 98% by squeezing a properly mode-matched mode. …”
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Direct spectrum analysis using a threshold detector with application to a superconducting circuit by G Ithier, G Tancredi, P J Meeson

“…We show that this new framework provides direct access to the environmental noise spectrum with a sensitivity approaching the standard quantum limit of weak continuous measurements. In addition, the accessible frequency range of the spectrum is, in principle, limited only by the ring down time of the resonant mode. …”
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Theory of coherent interaction-free detection of pulses by John J. McCord, Shruti Dogra, Gheorghe Sorin Paraoanu

“…We find that our protocol reaches the Heisenberg limit when evaluating the Fisher information at small strengths of the pulses we aim to detect—in contrast to the projective protocol that can only reach the standard quantum limit. We also demonstrate that the coherent protocol remains remarkably robust under errors such as pulse rotation phases and strengths, the effect of relaxation rates and detunings, as well as different thermalized initial states.…”
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Quantum mechanical derivation of radio-frequency-driven coherent beam oscillations in storage rings by J. Slim, N. N. Nikolaev, F. Rathmann, A. Wirzba

“…The study of the approach to the quantum ground state and the possibility to detect displacements of macroscopic bodies close to the quantum limit represent pressing challenges in modern physics. …”
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Oscillatory magnetoresistance in the charge-transfer salt beta "-(BEDT-TTF)2AuBr2 in magnetic fields up to 60 T: Evidence for field-induced Fermi-surface reconstruction. by House, A, Harrison, N, Blundell, S, Deckers, I, Singleton, J, Herlach, F, Hayes, W, Perenboom, J, Kurmoo, M, Day, P

“…It is found that frequency mixing effects at very high magnetic fields, observed in the Fourier spectra of the magnetoresistance, cannot be explained by the Shoenberg magnetic interaction, but are instead probably caused by oscillations in the chemical potential which become important as the extreme quantum limit is approached.…”

Linear magnetoresistance caused by mobility fluctuations in the n-doped Cd3As2 by Narayanan, A, Watson, MD, Blake, S, Chen, Y, Prabhakaran, D, Yan, B, Bruyant, N, Drigo, L, Mazin, I, Felser, C, Kong, T, Canfield, P, Coldea, A

“…We find the non-saturating linear magnetoresistance persist up to 65T and it is likely caused by disorder effects as it scales with the high mobility, rather than directly linked to Fermi surface changes even when approaching the quantum limit. From the observed quantum oscillations, we determine the bulk three-dimensional Fermi surface having signatures of Dirac behaviour with non-trivial Berry's phase shift, very light effective quasiparticle masses and clear deviations from the band-structure predictions. …”

Quantum dynamics and entanglement of spins on a square lattice. by Christensen, N, Rønnow, H, McMorrow, D, Harrison, A, Perring, T, Enderle, M, Coldea, R, Regnault, L, Aeppli, G

“…Whereas this intuition generally holds for ferromagnets, even as the size of the magnetic moment is reduced to that of a single electron spin (the quantum limit), it breaks down spectacularly for antiferromagnets, particularly in low dimensions. …”

Sensitive radio-frequency read-out of quantum dots using an ultra-low-noise SQUID amplifier by Schupp, FJ, Vigneau, F, Wen, Y, Mavalankar, A, Griffiths, J, Jones, GAC, Farrer, I, Ritchie, DA, Smith, CG, Camenzind, LC, Yu, L, Zumbühl, DM, Briggs, GAD, Ares, N, Laird, EA

“…The SQUID amplifier operates at a frequency near 200 MHz and achieves a noise temperature below 600 mK when integrated into a reflectometry circuit, which is within a factor 120 of the quantum limit. It enables a record sensitivity to capacitance of 0.07 aF/√Hz. …”

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 attain 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. …”

Analytical study of drift velocity in low dimensional devices by Ahmadi, Mohammad Taghi, Saad, Ismail, Riyadi, Munawar Agus, Ismail, Razali, Arora, Vijay K.

“…Understanding of quantum limit in low dimensional devices helps to develop the new device types same as Carbon Nanotube Field Effect Transistor (CNTFET) and Naonowire. …”
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Dynamical quantum phase transitions in a spinor Bose-Einstein condensate and criticality enhanced quantum sensing by Lu Zhou, Jia Kong, Zhihao Lan, Weiping Zhang

“…We also demonstrate that near the critical points parameter estimation beyond the standard quantum limit can be implemented. This work not only advances the exploration of excited-state quantum phase transitions via a scheme that can immediately be applied to a broad class of few-mode quantum systems, but also provides a new perspective on the relationship between quantum criticality and quantum enhanced sensing.…”
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Phase Sensitivity Improvement in Correlation-Enhanced Nonlinear Interferometers by Xinyun Liang, Zhifei Yu, Chun-Hua Yuan, Weiping Zhang, Liqing Chen

“…Compared with a conventional Mach–Zehnder interferometer, the sensitivity of a correlation-enhanced nonlinear interferometer can break the standard quantum limit. Phase sensitivity plays a significant role in the enhanced performance. …”
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Criticality-enhanced electric field gradient sensor with single trapped ions by Theodoros Ilias, Dayou Yang, Susana F. Huelga, Martin B. Plenio

“…By exploiting both dissipative criticality and efficient continuous readout, the sensor device achieves highly precise sensing of oscillating electric field gradients at a criticality-enhanced precision scaling beyond the standard quantum limit, which we demonstrate is robust to the experimental imperfections in real-world applications.…”
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Integrable active atom interferometry by Michael Kastner, Vincent Menet, Johannes N Kriel

“…Active interferometers are designed to enhance phase sensitivity beyond the standard quantum limit by generating entanglement inside the interferometer. …”
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Large-Scale Optical Neural Networks Based on Photoelectric Multiplication by Ryan Hamerly, Liane Bernstein, Alexander Sludds, Marin Soljačić, Dirk Englund

“…Simulations of the network using models for digit and image classification reveal a “standard quantum limit” for optical neural networks, set by photodetector shot noise. …”
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