The dissipative dynamics of a quantum bistable system coupled to a Ohmic heat bath is investigated beyond the spin-boson approximation. Within the path-integral approach to quantum dissipation, we propose an approximation scheme which exploits the separation of time scales between intra- and interwell (tunneling) dynamics. The resulting generalized master equation for the populations in a space localized basis enables us to investigate a wide range of temperatures and system-environment coupling strengths. A phase diagram in the coupling-temperature space is provided to give a comprehensive account of the different dynamical regimes.
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http://dx.doi.org/10.1103/PhysRevE.92.032123 | DOI Listing |
ACS Nano
January 2025
James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States.
Phonon dynamics and transport determine how heat is utilized and dissipated in materials. In 2D systems for optoelectronics and thermoelectrics, the impact of nanoscale material structure on phonon propagation is central to controlling thermal conduction. Here, we directly observe in-plane coherent acoustic phonon propagation in black phosphorus (BP) using ultrafast electron microscopy.
View Article and Find Full Text PDFPLoS One
January 2025
Computer Engineering, CCSIT, King Faisal University, Al Hufuf, Kingdom of Saudi Arabia.
This paper presents a low-power, second-order composite source-follower-based filter architecture optimized for biomedical signal processing, particularly ECG and EEG applications. Source-follower-based filters are recommended in the literature for high-frequency applications due to their lower power consumption when compared to filters with alternative topologies. However, they are not suitable for biomedical applications requiring low cutoff frequencies as they are designed to operate in the saturation region.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, 800 Dongchuan Road, 200240, Shanghai, CHINA.
Ionogels have attracted considerable attention as versatile materials due to their unique ionic conductivity and thermal stability. However, relatively weak mechanical performance of many existing ionogels has hindered their broader application. Herein, we develop robust, tough, and impact-resistant mechanically interlocked network ionogels (IGMINs) by incorporating ion liquids with mechanical bonds that can dissipate energy while maintain structural stability.
View Article and Find Full Text PDFDalton Trans
January 2025
College of Physics, Central South University, Changsha 410083, China.
Mid-infrared thermal radiation has attracted attention due to its wide range of applications. Compared to the static process of thermal emission, if thermal radiation can be dynamically controlled, it would be more suitable for practical applications. Herein, we designed a controllable thermal emitter based on phase change materials.
View Article and Find Full Text PDFClocks Sleep
January 2025
Circadian Physics Group, School of Physics, University of Sydney, Sydney, NSW 2006, Australia.
Fixed sleep schedules with an 8 h time in bed (TIB) are used to ensure participants are well-rested before laboratory studies. However, such schedules may lead to cumulative excess wakefulness in young individuals. Effects on older individuals are unknown.
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