With this work, we present two new methods for the generation of thermostatted, manifestly Hamiltonian dynamics and provide corresponding illustrations. The basis for this new class of thermostats is the peculiar thermodynamics as exhibited by logarithmic oscillators. These two schemes are best suited when applied to systems with a small number of degrees of freedom.
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http://dx.doi.org/10.1021/jp4020417 | DOI Listing |
Chaos
January 2025
School of Electronic Information, Central South University, Changsha 410083, China.
Memristors are commonly used to introduce various chaotic systems and can be used to enhance their chaotic characteristics. However, due to the strict construction conditions of Hamiltonian systems, there has been limited research on the development of memristive Hamiltonian conservative chaotic systems (MHCCSs). In this work, a method for constructing three-terminal memristors is proposed, and the three-terminal memristors are incorporated into the Hamiltonian system, resulting in the development of a class of n-D MHCCS.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
We outline two general theoretical techniques to simulate polariton quantum dynamics and optical spectra under the collective coupling regimes described by a Holstein-Tavis-Cummings (HTC) model Hamiltonian. The first one takes advantage of sparsity of the HTC Hamiltonian, which allows one to reduce the cost of acting polariton Hamiltonian onto a state vector to the linear order of the number of states, instead of the quadratic order. The second one is applying the well-known Chebyshev series expansion approach for quantum dynamics propagation and to simulate the polariton dynamics in the HTC system; this approach allows us to use a much larger time step for propagation and only requires a few recursive operations of the polariton Hamiltonian acting on state vectors.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
This study presents an efficient methodology for simulating nonadiabatic dynamics of complex materials with excitonic effects by integrating machine learning (ML) models with simplified Tamm-Dancoff approximation (sTDA) calculations. By leveraging ML models, we accurately predict ground-state wavefunctions using unconverged Kohn-Sham (KS) Hamiltonians. These ML-predicted KS Hamiltonians are then employed for sTDA-based excited-state calculations (sTDA/ML).
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Theoretical Physics, University of Debrecen, P.O. Box 400, Debrecen H-4002, Hungary.
The coupling of matter to the quantized electromagnetic field of a plasmonic or optical cavity can be harnessed to modify and control chemical and physical properties of molecules. In optical cavities, a term known as the dipole self-energy (DSE) appears in the Hamiltonian to ensure gauge invariance. The aim of this work is twofold.
View Article and Find Full Text PDFEntropy (Basel)
December 2024
Institute for Quantum Computing, Waterloo, ON N2L 3G1, Canada.
Understanding the flow, loss, and recovery of the information between a system and its environment is essential for advancing quantum technologies. The central spin system serves as a useful model for a single qubit, offering valuable insights into how quantum systems can be manipulated and protected from decoherence. This work uses the stimulated echo experiment to track the information flow between the central spin and its environment, providing a direct measure of the sensitivity of system/environment correlations to environmental dynamics.
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