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We performed ultrafast reflection-type pump-probe spectroscopy of coherent longitudinal optical (LO) phonons in a (001)-oriented semi-insulating GaAs crystal using femtosecond laser pulses optically transparent to GaAs. From the temporal oscillatory profile as a function of time delay, the decay time of the coherent LO phonons was estimated to be (4.4±0.15) ps. The present estimated decay time agrees with the decay time estimated with the use of coherent anti-Stokes Raman scattering spectroscopy: (4.2±0.4) ps [Phys. Rev. B49, 2460 (1994)10.1103/PhysRevB.49.2460]. The above-mentioned results indicate that the coherent LO phonons, which are observed using ultrafast pump-probe with femtosecond laser pulses transparent to the samples, have the same decay time obtained by coherent anti-Stokes Raman scattering spectroscopy.
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http://dx.doi.org/10.1364/AO.561770 | DOI Listing |
J Math Biol
September 2025
School of Mathematical Sciences and Institute of Natural Sciences, MOE-LSC, CMA-Shanghai, Shanghai Jiao Tong University, Shanghai, China.
It has been noticed that when the waiting time distribution exhibits a transition from an intermediate time power-law decay to a long-time exponential decay in the continuous time random walk model, a transition from anomalous diffusion to normal diffusion can be observed at the population level. However, the mechanism behind the transition of waiting time distribution is rarely studied. In this paper, we provide one possible mechanism to explain the origin of such a transition.
View Article and Find Full Text PDFSci Justice
September 2025
Department of Chemistry, Eberly College of Science, The Pennsylvania State University, University Park, PA, United States. Electronic address:
Given that a variety of factors can affect the decomposition process, it can be difficult to determine the post-mortem interval (PMI). The process is highly dependent on microbial activity, and volatile organic compounds (VOCs) are a by-product of this activity. Given both have been proposed to assist in PMI determination, a deeper understanding of this relationship is needed.
View Article and Find Full Text PDFJ Lipid Res
September 2025
Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8. Electronic address:
Young females have higher circulating docosahexaenoic acid (DHA) levels than males, though the metabolic basis remains incompletely understood. Building on previous findings demonstrating higher hepatic synthesis of the DHA precursor, docosapentaenoic acid (DPAn-3) in males, this study extends the investigation to n-3 PUFA turnover in extrahepatic tissues of male and female C57BL/6N mice using compound-specific isotope analysis (CSIA). Animals were fed a 12-week diet enriched in either α-linolenic acid (ALA), eicosapentaenoic acid (EPA), or DHA, starting with a 4-week phase containing low carbon-13 (δC)-n-3 PUFA, followed by an 8-week phase with high δC-n-3 PUFA (n = 4 per diet, time point, sex).
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Università degli Studi di Padova, Dipartimento di Fisica e Astronomia, Via Marzolo 8, 35131 Padova, Italy.
Feebly interacting particles, such as sterile neutrinos, dark photons, and axions, can be abundantly produced in the proto-neutron star (PNS) formed in core-collapse supernovae (CCSNe). These particles can decay into photons or charged leptons, depositing energy outside the PNS. Strong bounds on new particles can thus be derived from the observed luminosity of CCSNe, with even tighter bounds obtained from low-energy SNe observations.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
We analyze the impact of non-Markovian classical noise on single-qubit randomized benchmarking experiments, in a manner that explicitly models the realization of each gate via realistic finite-duration pulses. Our new framework exploits the random nature of each gate sequence to derive expressions for the full survival probability decay curve which are nonperturbative in the noise strength. In the presence of non-Markovian noise, our approach shows that the decay curve can exhibit a strong dependence on the gate implementation method, with regimes of both exponential and power law decays.
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