Article
Physics, Multidisciplinary
Aaron Z. Goldberg, Luis L. Sanchez-Soto, Hugo Ferretti
Summary: The quantum Cramer-Rao bound is crucial in modern quantum metrology for providing ultimate precision in parameter estimation. In multiparameter scenarios, this bound transforms into a matrix inequality that can be converted into scalar form with a chosen weight matrix, resulting in trade-offs in estimation precision for each parameter. By encoding information in a unitary transformation and selecting the weight matrix as the metric tensor, linked to the algebra Su(n) geometry, an intrinsic bound is established, independent of parametrization choice.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Nathan Shettell, William J. Munro, Damian Markham, Kae Nemoto
Summary: Noise is the greatest obstacle in quantum metrology that limits achievable precision and sensitivity. Quantum error correction can be beneficial, but with current technological limitations, achieving the Heisenberg limit remains challenging. Improvements in factors such as repetition frequency are needed to reliably reach the desired precision level.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
Xi-Yu Luo, Yong Yu, Jian-Long Liu, Ming-Yang Zheng, Chao-Yang Wang, Bin Wang, Jun Li, Xiao Jiang, Xiu-Ping Xie, Qiang Zhang, Xiao-Hui Bao, Jian-Wei Pan
Summary: This article reports the establishment of postselected entanglement between two physically separated atomic quantum memories. By sending, storing, and retrieving photons, a memory-memory entanglement fidelity of 90% was achieved. This experiment takes a significant step toward the realization of a practical metropolitan-scale quantum network.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Massimo Frigerio, Stefano Olivares, Matteo G. A. Paris
Summary: The paper proposes a post-selection protocol using single-photon subtraction and thermal states of radiation to achieve a larger information-cost ratio for temperature estimation. This scheme involves only classical states of radiation, which contrasts with recent results in unitary quantum statistical models where post-selection strategies can outperform direct protocols using nonclassical states.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Sarnava Datta, Hermann Kampermann, Dagmar Bruss
Summary: In this paper, we introduce a device-independent quantum key distribution (DIQKD) scenario where the security is ensured by constructing an optimal Bell inequality from the measurement data instead of predefining a specific Bell inequality. Our method can be applied to any number of measurement settings and outcomes, and we provide an implementable protocol for finite-size security key analysis against collective attacks.
Article
Quantum Science & Technology
Xuanhua Wang, Jin Wang
Summary: In this study, quantum master equations beyond secular approximation are used to study the nonequilibrium thermodynamic cost of enhanced quantum metrology and quantum correlations. It is found that nonequilibrium conditions enhance quantum Fisher information and quantum correlations predominantly for weak tunneling scenarios. However, in the strong tunneling regimes, the quantum Fisher information and quantum correlations cannot be continuously boosted by higher thermodynamic costs and decay once the system is overburdened with extremely large energy currents.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Optics
Seongjin Hong, Junaid ur Rehman, Yong-Su Kim, Young-Wook Cho, Seung-Woo Lee, Su-Yong Lee, Hyang-Tag Lim
Summary: This study investigates a strategy to achieve the best practical sensitivity by optimizing both mode-amplitudes of multi-mode N00N states and a split ratio of a multi-mode beam splitter, and experimentally demonstrates its effectiveness.
LASER & PHOTONICS REVIEWS
(2022)
Article
Physics, Multidisciplinary
Alessandro Candeloro, Matteo G. A. Paris, Marco G. Genoni
Summary: This study discusses the use of asymptotic incompatibility (AI) to assess the quantumness of quantum statistical models, showing a simple monotonous relationship between AI and state purity in certain cases.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Optics
Danilo Triggiani, Paolo Facchi, Vincenzo Tamma
Summary: The study proposes a metrological strategy for achieving Heisenberg-scaling precision in estimating functions of any fixed number of parameters. This scheme utilizes single-mode squeezed vacuum and homodyne detection, with two auxiliary linear networks playing a key role in refocusing the signal and fixing the function of the parameters to be estimated. The precision required for the prior measurement is shown to be achievable through classic measurement techniques.
Article
Quantum Science & Technology
Arne Hamann, Pavel Sekatski, Wolfgang Duer
Summary: This paper investigates the sensing of scalar valued fields with specific spatial dependence using a network of sensors. By constructing a decoherence-free subspace, the specific signal can be accurately sensed while being insensitive to other signals at different positions or with unequal spatial dependence. The concept of an approximate decoherence-free subspace is introduced to suppress noise while controlling the signal strength. An efficient formalism is introduced to construct internal states and sensor configurations, and several examples are analyzed and applied to demonstrate the usefulness and wide applicability of the approach.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Kai Sun, Zheng-Hao Liu, Yan Wang, Ze-Yan Hao, Xiao-Ye Xu, Jin-Shi Xu, Chuan-Feng Li, Guang-Can Guo, Alessia Castellini, Ludovico Lami, Andreas Winter, Gerardo Adesso, Giuseppe Compagno, Rosario Lo Franco
Summary: This study experimentally demonstrates the different contributions to quantum coherence from identical and nonidentical particles, and proves that independent indistinguishable particles can serve as controllable resources of coherence and entanglement.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Multidisciplinary
Michael J. W. Hall
Summary: This study utilizes the uncertainty relation of Renyi entropies to obtain a strong Heisenberg limit, which bounds the root mean square error of a random optical phase shift estimate in terms of average photon number. Simple yet powerful uncertainty relations linking phase uncertainty to photon number distribution are also provided. Furthermore, upper and lower bounds on the Renyi mutual information of quantum communication channels are used to obtain strong bounds on estimation of unitary shift parameters and coherence measures.
Article
Optics
Jun Xin, Ge LI
Summary: In this paper, a remote switch for Schrodinger's cat state is proposed, and an approximate cat state is demonstrated using nonlocal correlations. The hybrid projective measurement is used to manipulate the size and parity of the generated cat state. This remote switch opens up new ideas for subsequent protocols.
Article
Optics
Petr Zapletal, Tom Darras, Hanna Le Jeannic, Adrien Cavailles, Giovanni Guccione, Julien Laurat, Radim Filip
Summary: The research demonstrates that n independent imperfect single photons can ultimately bunch into the Fock state, introducing an experimental Fock-state bunching capability for single-photon sources. This operational approach, unlike autocorrelation functions, considers residual multi-photon components, vacuum admixture, and individual photon statistics' dispersion.
Article
Optics
Hamish Scott, Dominic Branford, Niclas Westerberg, Jonathan Leach, Erik M. Gauger
Summary: Two different interferometers, the Mach-Zehnder interferometer and the Hong-Ou-Mandel interferometer, exhibit different sensitivities to phase noise and delay when dealing with photon interference. The Mach-Zehnder interferometer provides more accurate estimation of path length difference, while the Hong-Ou-Mandel interferometer is more sensitive to the relative indistinguishability of photon pairs.
Article
Quantum Science & Technology
Akram Youssry, Robert J. Chapman, Alberto Peruzzo, Christopher Ferrie, Marco Tomamichel
QUANTUM SCIENCE AND TECHNOLOGY
(2020)
Article
Physics, Multidisciplinary
Jonathan A. Gross, Carlton M. Caves
Summary: It is challenging to establish achievable sensitivity bounds for quantum multiparameter estimation. In a special case where many parameters of a process are unknown, estimating a specific linear combination of these parameters without control is superficially similar to single-parameter estimation but retains genuinely multiparameter aspects. Geometric reasoning demonstrates the necessary and sufficient conditions for saturating the fundamental and attainable quantum-process bound in this context.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Editorial Material
Physics, Multidisciplinary
Joshua Combes
Summary: The unavoidable noise in quantum systems necessitates quantum error correction to maximize the potential of quantum computers. Autonomous error-correction devices can reduce computational and hardware overheads compared to traditional approaches.
Article
Physics, Multidisciplinary
Markus Rambach, Mahdi Qaryan, Michael Kewming, Christopher Ferrie, Andrew G. White, Jacquiline Romero
Summary: Self-guided tomography is demonstrated to be a practical, efficient, and robust technique for measuring higher-dimensional quantum states with high fidelities. The technique shows excellent performance for both pure and mixed states, achieving record high fidelities. It also exhibits robustness against various sources of experimental noise.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
Corey Rae H. McRae, Gregory M. Stiehl, Haozhi Wang, Sheng-Xiang Lin, Shane A. Caldwell, David P. Pappas, Josh Mutus, Joshua Combes
Summary: Accurate comparison of performance metrics among measurements, devices, and laboratories is crucial for optimizing superconducting quantum devices, but currently such comparisons are hindered by understudied errors from various sources. Further research is needed in error analysis for qubits and resonators in superconducting quantum circuits to progress towards device optimization.
APPLIED PHYSICS LETTERS
(2021)
Article
Education, Scientific Disciplines
Abraham Asfaw, Alexandre Blais, Kenneth R. Brown, Jonathan Candelaria, Christopher Cantwell, Lincoln D. Carr, Joshua Combes, Dripto M. Debroy, John M. Donohue, Sophia E. Economou, Emily Edwards, Michael F. J. Fox, Steven M. Girvin, Alan Ho, Hilary M. Hurst, Zubin Jacob, Blake R. Johnson, Ezekiel Johnston-Halperin, Robert Joynt, Eliot Kapit, Judith Klein-Seetharaman, Martin Laforest, H. J. Lewandowski, Theresa W. Lynn, Corey Rae H. McRae, Celia Merzbacher, Spyridon Michalakis, Prineha Narang, William D. Oliver, Jens Palsberg, David P. Pappas, Michael G. Raymer, David J. Reilly, Mark Saffman, Thomas A. Searles, Jeffrey H. Shapiro, Chandralekha Singh
Summary: The paper provides a roadmap for constructing a quantum engineering education program to meet the workforce needs of the United States and international community. Through a workshop and drawing on best practices, the researchers make specific findings and recommendations, including the design of a first quantum engineering course accessible to all STEM students and the education and training methods for producing quantum-proficient engineers.
IEEE TRANSACTIONS ON EDUCATION
(2022)
Correction
Quantum Science & Technology
Jonathan A. Gross, Carlton M. Caves, Gerard J. Milburn, Joshua Combes
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Editorial Material
Automation & Control Systems
Marco M. Nicotra, Jieqiu Shao, Joshua Combes, Anne Cross Theurkauf, Penina Axelrad, Liang-Ying Chih, Murray Holland, Alex A. Zozulya, Catie K. LeDesma, Kendall Mehling, Dana Z. Anderson
IEEE CONTROL SYSTEMS MAGAZINE
(2023)
Article
Physics, Multidisciplinary
B. D. Hauer, J. Combes, J. D. Teufel
Summary: We propose a technique to generate cat states of motion using the intrinsic nonlinearity of a dispersive optomechanical interaction. By applying a bichromatic drive to an optomechanical cavity, our protocol enhances the inherent second-order processes of the system, inducing the requisite two-phonon dissipation. We show that this nonlinear sideband cooling technique can dissipatively engineer a mechanical resonator into a cat state, which we verify using the full Hamiltonian and an adiabatically reduced model.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Joshua Combes, Austin P. Lund
Summary: Homodyne measurements are a commonly used quantum measurement method that limits to field quadrature measurement using a coherent state as the local oscillator. This paper presents a general idea that injecting nonclassical states as the local oscillator can lead to nonclassical measurements, with the specific example of injecting a superposition of coherent states, known as a Schrödinger cat state. The Kraus operators and positive operator-valued measure in this situation are derived.
Article
Optics
Jieqiu Shao, Joshua Combes, John Hauser, Marco M. Nicotra
Summary: This paper presents a general-purpose solver for quantum optimal control based on the PRONTO method. The method incorporates the Schrodinger equation into the cost function using a projection operator and minimizes it using Newton's descent method. The method guarantees monotonic convergence at each iteration and quadratic convergence near the solution.
Article
Optics
Jonathan A. Gross, Ben Q. Baragiola, T. M. Stace, Joshua Combes
Summary: This paper introduces a general purpose input-output theory for narrowband squeezed light, which focuses on the statistical characteristics of the squeezed field and the shape of the wave packet. It illustrates the non-Markovian nature of the field by studying the decay and resonance fluorescence of two-level atoms in the presence of such fields.
Article
Optics
Jeffrey M. Epstein, K. Birgitta Whaley, Joshua Combes
Summary: The article introduces a class of nonlinear amplifiers that amplify normal operators and add only half a quantum of vacuum noise at the output. In the large-gain limit, when used with noisy linear detectors, these amplifiers implement ideal measurements of the normal operator.
Article
Optics
Zhibo Hou, Jun-Feng Tang, Christopher Ferrie, Guo-Yong Xiang, Chuan-Feng Li, Guang-Can Guo