المؤلفون: Michie, Matthew J., Ekanayake, Nagitha, Weingartz, Nicholas P., Stamm, Jacob, Dantus, Marcos^1,2 dantus@chemistry.msu.edu

المصدر: Journal of Chemical Physics. 1/28/2019, Vol. 150 Issue 4, pN.PAG-N.PAG. 7p. 7 Graphs.

مصطلحات موضوعية: *QUANTUM coherence, *COHERENCE (Physics), *PHOTONS, *PHASE transitions, *POLYATOMIC molecules

مستخلص: Quantum coherent control (QCC) has been successfully demonstrated experimentally and theoretically for two- and three-photon optical excitation of atoms and molecules. Here, we explore QCC using spectral phase functions with a single spectral phase step for controlling the yield of H3+ from methanol under strong laser field excitation. We observe a significant and systematic enhanced production of H3+ when a negative 3 4 π phase step is applied near the low energy region of the laser spectrum and when a positive 3 4 π phase step is applied near the high energy region of the laser spectrum. In some cases, most notably the HCO+ fragment, we found the enhancement exceeded the yield measured for transform limited pulses. The observation of enhanced yield is surprising and far from the QCC prediction of yield suppression. The observed QCC enhancement implies an underlying strong field process responsible for polyatomic fragmentation controllable by easy to reproduce shaped pulses. [ABSTRACT FROM AUTHOR]

المؤلفون: Azuma, Hiroo¹ (AUTHOR) hiroo.azuma@m3.dion.ne.jp

المصدر: Journal of Physics D: Applied Physics. 2/16/2024, Vol. 57 Issue 7, p1-2. 2p.

مصطلحات موضوعية: *COHERENCE (Physics), *PHOTONIC crystals, *PHOTONIC crystal fibers, *INFANT formulas

مستخلص: Corrections of mistakes in the published paper (2023 J. Phys. D: Appl. Phys. 56 475101) are given. [ABSTRACT FROM AUTHOR]

المؤلفون: Varvelis, Evangelos, Biswas, Debjyoti, DiVincenzo, David P.

المصدر: Proceedings of the National Academy of Sciences of the United States of America; 1/23/2024, Vol. 121 Issue 4, p1-9, 9p

مصطلحات موضوعية: BELL'S theorem, ARBITRARY waveform generators, PHOTON detectors, QUANTUM cryptography, COHERENCE (Physics), PHOTON counting

مستخلص: We develop a photonic description of short, one-dimensional electromagnetic pulses, specifically in the language of electrical transmission lines. Current practice in quantum technology, using arbitrary waveform generators, can readily produce very short, few- cycle pulses in a very-low-noise, low-temperature setting. We argue that these systems attain the limit of producing pure coherent quantum states, in which the vacuum has been displaced for a short time, and therefore over a short spatial extent. When the pulse is bipolar, that is, the integrated voltage of the pulse is zero, then the state can be described by the finite displacement of a single mode. Therefore there is a definite mean number of photons, but which have neither a well-defined frequency nor position. Due to the Paley--Wiener theorem, the two-component photon "wavefunction" of this mode, while somewhat localized, is not strictly bounded in space even if the vacuum displacement that defines it is bounded. When the pulse is unipolar, no photonic description is possible--the photon number can be considered to be divergent. We consider properties that photon counters and quantum non-demolition detectors must have to optimally convert and detect the photons in several example pulses. We develop a conceptual test system for implementing short-pulse quantum key distribution, building on the design of a recently achieved Bell's theorem test in a cryogenic microwave setup. [ABSTRACT FROM AUTHOR]

: Copyright of Proceedings of the National Academy of Sciences of the United States of America is the property of National Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Yu, Nanxin, Geng, Wenping, Liu, Yukai, Zhang, Huiyi, Lu, Hao, Duan, Zhigang, Yang, Lingxiao, Zhang, Yichi, Chou, Xiujian

المصدر: Analytical & Bioanalytical Chemistry; Jan2024, Vol. 416 Issue 2, p509-518, 10p

مصطلحات موضوعية: ACOUSTIC surface waves, SPHERICAL waves, HUYGENS-Fresnel principle, ACOUSTIC field, ERYTHROCYTES, PHONONIC crystals, COHERENCE (Physics)

مستخلص: The application of standing surface acoustic wave (SSAW) tweezers based on backpropagation superposition to achieve precise behavior manipulation of microscale cells and even nanoscale bacteria has been widely studied and industrialized. However, the structure requires multiple transducer components or full channel resonance. It is very challenging to design a simple structure for nano-control by complex acoustic field. In this study, a reflector-interdigital transducer (R-IDT) acoustofluidic device based on unilateral coherence enhancement is proposed to achieve SSAW definition features of periodic particle capture positions. The SAW device based on a unilateral transducer can not only generate leaky-SAW in water-filled microchannel, but also have a contribution of spherical waves in the vibration area of the substrate-liquid interface due to the Huygens-Fresnel diffractive principle. Both of them form a robust time-averaged spatial periodicity in the pressure potential gradient, accurately predicting the lateral spacing of these positions through acoustic patterning methods. Furthermore, a reflector based on Bragg-reflection is used to suppress backward transmitted SAW and enhance forward conducted SAW beams. By using a finite element model, R-IDT structure's amplitude enhances 60.78% compared to single IDT structure. The particle manipulation range of the diffractive acoustic field greatly improves, verified by experimental polystyrene microspheres. Besides, biocompatibility is conformed through red blood cells and Bacillus subtilis. We investigate the overall shift of periodic pressure field that can still occur when the phase changes. This work provides a simpler and low-cost solution for the application of acoustic tweezer in biological cell culture and filtering. [ABSTRACT FROM AUTHOR]

: Copyright of Analytical & Bioanalytical Chemistry is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Ding, Cai Rong, Zeng, Xue Ran, Liang, Chao Lun, Lv, Ze Sheng, Wang, Zi Xin

المصدر: Physica Status Solidi (B); Jan2024, Vol. 261 Issue 1, p1-7, 7p

مصطلحات موضوعية: CATHODOLUMINESCENCE, ZINC oxide, COHERENCE (Physics), NANOSTRUCTURED materials, OPTOELECTRONIC devices, SCANNING electron microscopes, POWER density

مستخلص: ZnO nanostructures are attractive candidates as source media for realizing optoelectronic devices. Based on the comparison of cathodoluminescence images and scanning electron microscope morphology images, the mixing color images of ZnO nanosheets indicate that the emission of the ZnO nanosheet is emitted from its flat surface. In time‐resolved photoluminescence, a sharp emission pulse is observed after the delay time τD of 56 ps relative to zero time at the threshold excitation power, the pulse peak intensity exhibits a superlinear increase proportional to P2.7 (P is the excitation power density), the reduction of τD is proportional to ln(P)/P$\text{ln} \left(\right. P \left.\right) / P$, oscillation is demonstrated in the decay trace at high excitation power, and the time interval of two oscillation emissions is 36 ps. Experimental results indicate that superfluorescence (SF) is demonstrated at room temperature and it is assigned to coherent dipole states in the population version localized to approximately 3 nm thick ZnO nanosheet. SF of coherent dipole states is characterized by the delay time τD—the unique feature of SF and the Burnham–Chiao ringing behavior. Experimental observation of SF of ZnO nanosheets may have potential value for the investigation of room temperature many‐body quantum phenomena, coherent control, and applications for high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

: Copyright of Physica Status Solidi (B) is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المصدر: International Journal of Quantum Information; Dec2023, Vol. 21 Issue 8, p1-5, 5p

مصطلحات موضوعية: DEEP learning, QUANTUM computers, COHERENCE (Physics), QUANTUM entropy, BELL'S theorem, QUANTUM teleportation, QUANTUM computing, ENTROPY

المؤلفون: Ilyakov, Igor, Brataas, Arne, de Oliveira, Thales V. A. G., Ponomaryov, Alexey, Deinert, Jan-Christoph, Hellwig, Olav, Faßbender, Jürgen, Lindner, Jürgen, Salikhov, Ruslan, Kovalev, Sergey

المصدر: Nature Communications; 11/2/2023, Vol. 14 Issue 1, p1-8, 8p

مصطلحات موضوعية: FREQUENCY changers, SECOND harmonic generation, REAL-time computing, SUBMILLIMETER waves, SEEBECK effect, LATTICE dynamics, COHERENCE (Physics)

مستخلص: Efficient generation and control of spin currents launched by terahertz (THz) radiation with subsequent ultrafast spin-to-charge conversion is the current challenge for the next generation of high-speed communication and data processing units. Here, we demonstrate that THz light can efficiently drive coherent angular momentum transfer in nanometer-thick ferromagnet/heavy-metal heterostructures. This process is non-resonant and does neither require external magnetic fields nor cryogenics. The efficiency of this process is more than one order of magnitude higher as compared to the recently observed THz-induced spin pumping in MnF2 antiferromagnet. The coherently driven spin currents originate from the ultrafast spin Seebeck effect, caused by a THz-induced temperature imbalance in electronic and magnonic temperatures and fast relaxation of the electron-phonon system. Owing to the fact that the electron-phonon relaxation time is comparable with the period of a THz wave, the induced spin current results in THz second harmonic generation and THz optical rectification, providing a spintronic basis for THz frequency mixing and rectifying components. Terahertz frequencies offer the potential of much higher data transfer rates, but this requires devices able to generate and manipulate terahertz waves. One approach is to utilize the spin dynamics of a magnetic system. Here, Ilyakov et al. show how a multilayer magnetic and heavy-metal heterostructure can be used to achieve terahertz second harmonic generation and optical rectification. [ABSTRACT FROM AUTHOR]

: Copyright of Nature Communications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Baltikas, Vasilis, Krestenitis, Yannis N.

المصدر: Journal of Marine Science & Engineering; Nov2023, Vol. 11 Issue 11, p2066, 17p

مصطلحات موضوعية: WATER waves, OCEAN waves, STOCHASTIC models, COHERENCE (Physics)

مستخلص: A numerical stochastic wave model was developed in this study based on the quasi-coherent theoretical framework proposed by Smit and Janssen in 2013. Subsequently, the model was implemented to reproduce and cross-confirm the findings of the quasi-coherent (QC) spectral wave modeling approach. The process included simulations of experiments conducted by Vincent and Briggs regarding waves propagating over a submerged shoal. The results of the simulations agree with the expected results of the QC theory, which can account for the spatial coherence of inhomogeneous wave fields and capture wave interference more accurately than conventional spectral wave models. In addition, extra insight was gained about aspects of the overall numerical implementation of the QC theory. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of Marine Science & Engineering is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Khachatrian, A. Zh.¹ ashot.khachatrian@gmail.com

المصدر: Armenian Journal of Physics. 2022, Vol. 15 Issue 4, p120-124. 5p.

مصطلحات موضوعية: *COHERENCE (Physics)

مستخلص: The paper discusses the problem of a superposition wave field created by a system of coherent point sources. For the general case, the conditions for a point amplification of the superposition field are found. The focusing problem is discussed for a system of point sources located on circles with centers lying on the same straight line parallel to the planes of the circles. [ABSTRACT FROM AUTHOR]

المؤلفون: Gorbunov, A. V.¹ (AUTHOR) gorbunov@issp.ac.ru, Timofeev, V. B.¹ (AUTHOR)

المصدر: Journal of Experimental & Theoretical Physics. Oct2022, Vol. 135 Issue 4, p458-472. 15p.

مصطلحات موضوعية: *CONDENSED matter, *COHERENCE (Physics), *ELECTROMAGNETIC fields, *DIELECTRICS, *BOSONS, *CYCLOTRONS

مستخلص: A review of experimental studies of the properties of a recently discovered new coherent collective state, a magnetoexciton condensate, is presented. Condensation occurs at temperatures below 1 K in a Fermi system, a quantum Hall insulator (a filling factor of ν = 2), as a result of the formation of a dense ensemble of long-lived triplet spin cyclotron magnetoexcitons—composite bosons. The condensed phase interacts coherently with an external electromagnetic field and demonstrates the ability of fast nondiffusive propagation over macroscopic distances and high spatial coherence. [ABSTRACT FROM AUTHOR]