51 research outputs found
supplemental_file – Supplemental material for Comparison of two cardiopulmonary bypass strategies with a miniaturized tubing system: a propensity score–based analysis
No full textSupplemental material, supplemental_file for Comparison of two cardiopulmonary bypass strategies with a miniaturized tubing system: a propensity score–based analysis by Cheng Zhang, Baoying Meng, Keye Wu and Yiqun Ding in Perfusion</p
sj-pdf-1-prf-10.1177_0267659120967206 – Supplemental material for Impact of miniaturized cardiopulmonary bypass circuits on ultrafiltration during congenital heart surgery
No full textSupplemental material, sj-pdf-1-prf-10.1177_0267659120967206 for Impact of miniaturized cardiopulmonary bypass circuits on ultrafiltration during congenital heart surgery by Keye Wu, Baoying Meng, Yuanxiang Wang, Xing Zhou, Sheshe Zhang and Yiqun Ding in Perfusion</p
Optomechanical preparation of photon number-squeezed states with a pair of thermal reservoirs of opposite temperatures
No full textPhoton number-squeezed states are of significant value in fundamental quantum
research and have a wide range of applications in quantum metrology. Most of
their preparation mechanisms require precise control of quantum dynamics and
are less tolerant to dissipation. We propose a mechanism that is not subject to
these restraints. In contrast to common approaches, we exploit the
self-balancing between two types of dissipation induced by positive- and
negative-temperature reservoirs to generate steady states with sub-Poissonian
statistical distributions of photon numbers. We also show how to implement this
mechanism with cavity optomechanical systems. The quality of the prepared
photon number-squeezed state is estimated by our theoretical model combined
with realistic parameters for various typical optomechanical systems.Comment: 10 pages, 3 figures, 90 referances
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Relativistic Measurement Backaction in the Quantum Dirac Oscillator
No full textAn elegant method to circumvent quantum measurement backaction is the use of quantum mechanics free subsystems (QMFS), with one approach involving the use of two oscillators with effective masses of opposite signs. Since negative energies, and hence masses, are a characteristic of relativistic systems a natural question is to what extent QMFS can be realized in this context. Using the example of a one-dimensional Dirac oscillator we investigate conditions under which this can be achieved, and identify Zitterbewegung or virtual pair creation as the physical mechanism that fundamentally limits the feasibility of the scheme. We propose a tabletop implementation of a Dirac oscillator system based on a spin-orbit coupled ultracold atomic sample that allows for a direct observation of the corresponding analog of virtual pair creation on quantum measurement backaction.National Key Research and Development Program of China [2016YFA0302001]; National Natural Science Foundation of China [11574086, 91436211, 11654005, 11234003, 11374003]; Shanghai Rising-Star Program [16QA1401600]; Science and Technology Commission of Shanghai Municipality [16DZ2260200]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Dissipative quantum Fisher information for a general Liouvillian parameterized process
No full textThe dissipative quantum Fisher information (DQFI) for a dynamic map with a
general parameter in an open quantum system is investigated, which can be
regarded as an analog of the quantum Fisher information (QFI) in the Liouville
space. We first derive a general dissipative generator in the Liouville space,
and based on its decomposition form, find the DQFI stems from two parts. One is
the dependence of eigenvalues of the Liouvillian supermatrix on the estimated
parameter, which shows a linear dependence on time. The other is the variation
of the eigenvectors with the estimated parameter. The relationship between this
part and time presents rich characteristics, including harmonic oscillation,
pure exponential gain and attenuation, as well as exponential gain and
attenuation of oscillatory type, which depend specifically on the properties of
the Liouville spectrum. This is in contrast to that of the conventional
generator, where only oscillatory dependencies are seen. Further, we illustrate
the theory through a toy model: a two-level system with spin-flip noise.
Especially, by using the DQFI, we demonstrated that the exceptional estimation
precision cannot be obtained at the Liouvillian exceptional point.Comment: 22 pages, 4 figures
Enhanced Quantum Metrology with Non-Phase-Covariant Noise
No full textThe detrimental impact of noise on sensing performance in quantum metrology has been widely recognized by researchers in the field. However, there are no explicit fundamental laws of physics stating that noise invariably weakens quantum metrology. We reveal that phase-covariant (PC) noise either degrades or remains neutral to sensing precision, whereas non-phase-covariant (NPC) noise can potentially enhance parameter estimation, surpassing even the ultimate precision limit achievable in the absence of noise. This implies that a non-Hermitian quantum sensor may outperform its Hermitian counterpart in terms of sensing performance. To illustrate and validate our theory, we present several paradigmatic examples of magnetic field metrology.19 pages, 5 figure
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