Article
Chemistry, Physical
Shreyas Malpathak, Nandini Ananth
Summary: The mixed quantum classical (MQC)-initial value representation (IVR) is a semiclassical framework that selectively quantizes the modes of a complex system. It accurately reproduces nuclear quantum coherences and conserves zero-point energy in the quantum limit, but is less accurate in the classical limit. By modifying the MQC approach, we show analytically that it is exact for all correlation functions at time zero and numerically demonstrate its correctness in capturing the quantum and classical limits of zero-point energy (ZPE) flow. Interestingly, selective quantization of the system allows for prediction and modification of ZPE flow direction.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sameernandan Upadhyayula, Eli Pollak
Summary: The instanton expression for the thermal transmission probability through a one-dimensional barrier is derived using the uniform semiclassical energy-dependent transmission coefficient of Kemble. The resulting theory is smooth and does not diverge at the crossover temperature. The theory is improved by ensuring that at high energies, the integrand decays exponentially according to the Boltzmann factor, leading to a classical behavior at sufficiently high temperatures.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Sameernandan Upadhyayula, Eli Pollak
Summary: The instanton expression for the thermal transmission probability through a one-dimensional barrier is derived using the uniform semiclassical energy-dependent transmission coefficient of Kemble. The resulting theory does not diverge at the crossover temperature and is an improvement over the traditional instanton theory. It can be reduced to the classical theory at high temperatures and provides accurate results in applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Physics, Nuclear
A. G. Magner, A. Sanzhur, S. N. Fedotkin, A. Levon, S. Shlomo
Summary: The study derives the level density rho(E, A) for a one-component nucleon system using mean-field semiclassical periodic-orbit theory, showing the relationship with modified Bessel functions of entropy and discussing the role of fixed spin variables in rotating nuclei. It also discusses the behavior of rho when related to large and small excitation energies, as well as the importance of considering shell and pairing effects in fitting experimental data.
Article
Astronomy & Astrophysics
Chen Lan, Yi-Fan Wang
Summary: In this paper, the concept of ridgelines is introduced to investigate the semiclassical predictions of wave packets with arbitrary widths in quantum mechanics and quantum cosmology. The contour and the stream approaches are used for the exact calculation of the ridgelines. The results show that the semiclassical predictions in toy models have more abundant solutions than the classical theory, and interestingly, they may deviate from classical solutions due to quantum corrections.
Article
Chemistry, Physical
Maximilian A. C. Saller, Yifan Lai, Eitan Geva
Summary: This study demonstrates that combining the linearized semiclasscial approximation with Fermi's golden rule rate theory can provide a general and efficient computational framework to accurately capture the cavity-induced rate enhancement of charge transfer reactions in a molecular system placed inside a microcavity.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Vladimir V. Rybkin
Summary: The research on embedding potential using products of atomic orbital basis functions offers a new approach in the context of density functional embedding theory, allowing for the treatment of pseudopotential and all-electron calculations in a compact matrix form. With cost reduction procedures and population analysis based potential reduction, the method provides a simplified way to handle basis sets and potentials. Implemented for various systems, including proton-transfer reactions and density of states calculations, the method shows potential for large-scale applications to extended systems.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Physics, Multidisciplinary
Constantin Babenko, Frank Goehmann, Karol K. Kozlowski, Jesko Sirker, Junji Suzuki
Summary: A newly developed thermal form factor expansion method is applied to evaluate real-time longitudinal spin-spin correlation functions of the spin-1/2 XXZ chain in the antiferromagnetically ordered regime at zero temperature. The analytical result obtained incorporates all types of excitations in the model, allowing for accurate calculation of real-time correlations in this strongly interacting quantum system for arbitrary distances and times.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
Alan Scheidegger, Jiri Vanicek, Nikolay V. Golubev
Summary: By using advanced computational methods and efficient nuclear dynamics evaluation, we conducted a comprehensive study on small polyatomic molecules with long-lasting oscillatory dynamics of electron density triggered by outer-valence ionization. We found that in most molecules, the sudden removal of an electron either does not lead to the appearance of electronic coherence or the created coherences are quickly damped by nuclear rearrangement within a few femtoseconds. However, we identified several unexplored molecules with electron coherences lasting up to 10 fs, which can be promising candidates for experimental studies. Furthermore, we performed full-dimensional simulations of electron coherences coupled with nuclear motion in several molecules that were previously only studied under the fixed nuclei approximation.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Physics, Mathematical
Theotime Girardot, Nicolas Rougerie
Summary: In two-dimensional space, it is possible for quasi-particles to continuously interpolate between bosonic and fermionic quantum statistics. The ground state of a gas of anyons can be described to leading order by a semi-classical energy functional, displaying anyonic behavior in its momentum distribution. The study is based on coherent states, Husimi functions, the Diaconis-Freedman theorem, and a quantitative version of a semi-classical Pauli principle.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2021)
Article
Optics
Philip Daniel Blocher, Serwan Asaad, Vincent Mourik, Mark A. Johnson, Andrea Morello, Klaus Molmer
Summary: Out-of-time-ordered correlation functions (OTOCs) are crucial in studying quantum information scrambling, but are difficult to measure experimentally. This study proposes an OTOC measurement protocol that does not rely on time reversal and is applicable to various experimental settings and systems.
Article
Chemistry, Physical
Jia-Xi Zeng, Shuo Yang, Yu-Cheng Zhu, Wei Fang, Ling Jiang, En-Ge Wang, Dong H. Zhang, Xin-Zheng Li
Summary: In this study, the harmonic inversion technique was applied to extract vibrational eigenvalues from semiclassical initial values using explicit potential surfaces. The cross-correlation filter-diagonalization (CCFD) method was used for the inversion problem instead of Fourier transformation, resulting in shorter propagation time and avoiding numerical divergence issues. Additionally, the Divide-and-Conquer technique was employed to control the total dimensions, enhancing the numerical behavior and stability of the calculations. The results demonstrate the effectiveness of the CCFD method in extracting vibrational eigenvalues from short trajectories and reproducing spectra obtained from long-time trajectories, without sacrificing accuracy and with improved numerical behavior.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Multidisciplinary Sciences
Rafael Carballeira, David Dolgitzer, Peng Zhao, Debing Zeng, Yusui Chen
Summary: The study presents a new evolution equation for two-time correlation functions of a generalized non-Markovian open quantum system based on a modified stochastic Schrodinger equation approach. By simplifying and obtaining the two-time reduced propagator, computation costs can be saved and the converging process accelerated. This method can be widely applied to various open quantum models, particularly large-scale systems, and extend quantum regression theory to the non-Markovian case.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Jia-Xi Zeng, Shuo Yang, Yu-Cheng Zhu, Wei Fang, Ling Jiang, En-Ge Wang, Dong H. Zhang, Xin-Zheng Li
Summary: We applied the harmonic inversion technique to extract vibrational eigenvalues from the semiclassical initial value representation (SC-IVR) propagator of molecular systems. The cross-correlation filter-diagonalization (CCFD) method was used for inversion, avoiding numerical divergence issues and approximation problems. The Divide-and-Conquer technique was also used to enhance numerical behavior and stability. Results showed that CCFD effectively extracted vibrational eigenvalues from short trajectories, with no loss in accuracy compared to long-time results.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Optics
L. G. Liao, Q. Z. Xia, J. Cai, J. Liu
Summary: This study investigates the photoelectron momentum distribution of ionized atoms irradiated by an intense laser. The holography interference patterns in the distribution provide important information about the initial wavefunction and atomic potential experienced by the electron. The study reveals the deflection of semiclassical trajectories by the combined Coulomb potential and laser field and the distribution of initial momenta on a ring-shaped curve. The quantum interference of these trajectories dramatically alters the scattering amplitudes, leading to the glory rescattering effect.
