The ability to accurately simulate the time evolu-tion of quantum systems stands as a cornerstone of modern molecular science.It provides the essential mechanistic bridge between a system’s microscopic structure and ...The ability to accurately simulate the time evolu-tion of quantum systems stands as a cornerstone of modern molecular science.It provides the essential mechanistic bridge between a system’s microscopic structure and its macroscopic function,a challenge first envisioned by Feynman.The central difficulty,and the unifying theme of this Special Topic,is the problem of“complexity”:a multifaceted challenge arising from the interplay of strongly coupled electronic and vibrational degrees of freedom,quantum statistics,and the non-trivial,often non-Markovian,memory effects exerted by a surrounding environment.展开更多
Static disorder plays a crucial role in the electronic dynamics and spec-troscopy of complex molecular sys-tems.Traditionally,obtaining ob-servables averaged over static disor-der requires thousands of realiza-tions v...Static disorder plays a crucial role in the electronic dynamics and spec-troscopy of complex molecular sys-tems.Traditionally,obtaining ob-servables averaged over static disor-der requires thousands of realiza-tions via direct sampling of the dis-order distribution,leading to high computational costs.In this work,we extend the auxiliary degree-of-freedom based matrix product state(MPS)method to handle system-bath correlated thermal equilibrium initial states,which can capture static disorder effects using a one-shot quantum dynamical simulation.We validate the effectiveness of the extended method by computing the dipole-dipole time correlation function of the Holstein model relevant to the emission spectrum of molecular aggregates.Our results show that the one-shot method is very accu-rate with only a moderate increase in MPS bond dimension,thereby significantly reducing computational cost.Moreover,it enables the generation of a much larger number of samples than the conventional direct sampling method at negligible additional cost,thus reducing sta-tistical errors.This method provides a broadly useful tool for calculating equilibrium time cor-relation functions in system-bath coupled models with static disorder.展开更多
In this study,six-dimensional(6D)time-dependent wave packet calcula-tions were employed to investigate the dissociation of HCl molecules on two bimetallic surfaces,Cu/Ag(111)and Cu/Au(111).These calculations were base...In this study,six-dimensional(6D)time-dependent wave packet calcula-tions were employed to investigate the dissociation of HCl molecules on two bimetallic surfaces,Cu/Ag(111)and Cu/Au(111).These calculations were based on two accurate potential energy surfaces(PESs)constructed using neu-ral network methodology.Density functional theory(DFT)calculations revealed that the static barrier heights for HCl on Cu/Ag(111)and Cu/Au(111)were 0.32 eV and 0.28 eV,respectively.These values are significantly lower than the barrier height on pure Cu(111)(0.52 eV),primarily due to surface strain effects.However,it was found that the 6D dissociation probability of HCl in(v=0,1,j=0)states on Cu/Au(111)was considerably lower,despite its barrier height being 0.04 eV lower than that for Cu/Ag(111).The underlying mechanism for this observation was attributed to the non-monotonic dependence of the minimum energy path(MEP)on the molecular orientation,which was induced by charge transfer effect for HCl+Cu/Au(111).In contrast,HCl+Cu/Ag(111)exhibited a monotonic dependence.These contrasting behaviors led to dis-tinct differences in rotational alignment and excitation effects for the two reactions.展开更多
The wave function temporal evolution on the one-dimensional （ID） lattice is considered in the tight-binding approxi- mation. The lattice consists of N equal sites and one impurity site （donor）. The donor differs f...The wave function temporal evolution on the one-dimensional （ID） lattice is considered in the tight-binding approxi- mation. The lattice consists of N equal sites and one impurity site （donor）. The donor differs from other lattice sites by the on-site electron energy E and the intersite coupling C. The moving wave packet is formed from the wave function initially localized on the donor. The exact solution for the wave packet velocity and the shape is derived at different values E and C. The velocity has the maximal possible group velocity v = 2. The wave packet width grows with time -t1/3 and its amplitude decreases ,- t-1/3. The wave packet reflects multiply from the lattice ends. Analytical expressions for the wave packet front propagation and recurrence are in good agreement with numeric simulations.展开更多
Quantum dynamics calculations for the title reaction H（2S） ＋ S2（X3∑g） → SH（X2П） ＋S（3P） are performed byusing a globally accurate double many-body expansion potential energy surface [J. Phys. Chem. A 115 5...Quantum dynamics calculations for the title reaction H（2S） ＋ S2（X3∑g） → SH（X2П） ＋S（3P） are performed byusing a globally accurate double many-body expansion potential energy surface [J. Phys. Chem. A 115 5274 （2011）]. The Chebyshev real wave packet propagation method is employed to obtain the dynamical information, such as reaction probability, initial state-specified integral cross section, and thermal rate constant. It is found not only that there is a reaction threshold near 0.7 eV in both reaction probabilities and integral cross section curves, but also that both the probability and cross section increase firstly and then decrease as the collision energy increases. The existence of the resonance structure in both the probability and cross section curves is ascribed to the deep potential well. The calculation of the rate constant reveals that the reaction occurring on the potential energy surface of the ground-state HS2 is slow to take place.展开更多
In this work, we discuss the topological transformation of quantum dynamics by showing the wave dynamics of a quantum particle on different types of topological structures in various dimensions from the fundamental po...In this work, we discuss the topological transformation of quantum dynamics by showing the wave dynamics of a quantum particle on different types of topological structures in various dimensions from the fundamental polygons of the corresponding universal covering spaces. This is not the view from different perspectives of an observer who simply uses different coordinate systems to describe the same physical phenomenon but rather possible geometric and topological structures that quantum particles are endowed with when they are identified with differentiable manifolds that are embedded or immersed in Euclidean spaces of higher dimension. We present our discussions in the form of Bohr model in one, two and three dimensions using linear wave equations. In one dimension, the fundamental polygon is an interval and the universal covering space is the straight line and in this case the standing wave on a finite string is transformed into the standing wave on a circle which can be applied into the Bohr model of the hydrogen atom. In two dimensions, the fundamental polygon is a square and the universal covering space is the plane and in this case, the standing wave on the square is transformed into the standing wave on different surfaces that can be formed by gluing opposite sides of the square, which include a 2-sphere, a 2-torus, a Klein bottle and a projective plane. In three dimensions, the fundamental polygon is a cube and the universal covering space is the three-dimensional Euclidean space. It is shown that a 3-torus and the manifold K?× S1?defined as the product of a Klein bottle and a circle can be constructed by gluing opposite faces of a cube. Therefore, in three-dimensions, the standing wave on a cube is transformed into the standing wave on a 3-torus or on the manifold K?× S1. We also suggest that the mathematical degeneracy may play an important role in quantum dynamics and be associated with the concept of wavefunction collapse in quantum mechanics.展开更多
We present a quantum dynamics study on the isotope effects of hydro-gen transfer isomerization in the formic acid dimer,and this is achieved by multidimensional dy-namics calculations with an efficient quantum mechani...We present a quantum dynamics study on the isotope effects of hydro-gen transfer isomerization in the formic acid dimer,and this is achieved by multidimensional dy-namics calculations with an efficient quantum mechanical theoretical scheme developed by our group,on a full-dimensional neural network ab initio potential energy surface.The ground-state and fundamental tun-neling splittings for four deuterium isotopologues of formic acid dimer are considered,and the calculated results are in very good general agreement with the avail-able experimental measurements.Strong isotope effects are revealed,the mode-specific funda-mental excitation effects on the tunneling rate are evidently influenced by the deuterium sub-stitution of H atom with the substitution on the OH bond being more effective than on the CH bond.Our studies are helpful for acquiring a better understanding of isotope effects in the double-hydrogen transfer processes.展开更多
The unified bound on the fundamental limit of quantum dynamics rate, as quietly recently obtainedby Levitin and Toffoli [Phys.Rev.Lett.103 (2009) 160502], is improved and refined.The improvement may bearbitrarily larg...The unified bound on the fundamental limit of quantum dynamics rate, as quietly recently obtainedby Levitin and Toffoli [Phys.Rev.Lett.103 (2009) 160502], is improved and refined.The improvement may bearbitrarily large in certain cases.In particular, this puts a limit on the operation rate of quantum gates allowed byquantum mechanics.展开更多
We perform accurate quantum dynamcs calculations on the isomerization of vinylidene-acetylene.Large-scale parallel computations are accomplished by an efficient theoretical scheme developed by our group,in which the b...We perform accurate quantum dynamcs calculations on the isomerization of vinylidene-acetylene.Large-scale parallel computations are accomplished by an efficient theoretical scheme developed by our group,in which the basis functions are customized for the double-H transfer process.The A_(1)' and B_(2)'' vinylidene and delocalization states are obtained.The peaks recently observed in the cryo-SEVI spectra are analyzed,and very good agreement for the energy levels is achieved between theory and experiment.The discrepancies of energy levels between our calculations and recent experimental cryo-SEVI spectra are of similar magnitudes to the experimental error bars,or≤30 cm^(-1) excluding those involving the excitation of the CCH_(2) scissor mode.A kind of special state,called the isomerization state,is revealed and reported,which is characterized by large probability densities in both vinylidene and acetylene regions.In addition,several states dominated by vinylidene character are reported for the first time.The present work would contribute to the understanding of the double-H transfer.展开更多
Six-dimensional quantum dynamics calculations for the state-to-state scattering of H_(2)/D_(2) on the rigid Cu(100)surface have been carried out using a time-dependent wave packet approach,based on an accurate neural ...Six-dimensional quantum dynamics calculations for the state-to-state scattering of H_(2)/D_(2) on the rigid Cu(100)surface have been carried out using a time-dependent wave packet approach,based on an accurate neural network potential energy surface fit for thousands of density functional theory data computed with the opt PBE-vd W density functional.The present results are compared with previous theoretical and experimental ones regarding to the rovibrationally(in)elastic scattering of H_(2) and D_(2) from Cu(100).In particular,we test the validity of the site-averaging approximation in this system by which the six-dimensional(in)elastic scattering probabilities are compared with the weighted average of four-dimensional results over fifteen fixed sites.Specifically,the site-averaging model reproduces vibrationally elastic scattering probabilities quite well,though less well for vibrationally inelastic results at high energies.These results support the use of the site-averaging model to reduce computational costs in future investigations on the state-to-state scattering dynamics of heavy diatomic or polyatomic molecules from metal surfaces,where full-dimensional calculations are too expensive.展开更多
The mode selectivity of the H+CH_(3)D→H_(2)+CH_(2)D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method.The reaction dynamics are studied for the reactant CH_(3)D initial...The mode selectivity of the H+CH_(3)D→H_(2)+CH_(2)D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method.The reaction dynamics are studied for the reactant CH_(3)D initially from the ground state,the CH_(3) symmetry and asymmetry stretching excitation,the CD stretching excitation and the fundamental and the first overtone of the CH_(3) bending mode.The calculated reaction probabilities show that exciting either of the CH_(3) stretching modes enhances the reactivity in the collision energy range below 1.0 eV,while the CD stretching excitation does not obviously prompt the reaction.Fundamental CH_(3) bending excitation has nearly no effect on promoting reactivity.However,a significant enhancement is observed for the first overtone excitation of the CH_(3) bending mode,resulting from the Fermi resonance between the fundamental state of the CH_(3) symmetry stretching mode and the first overtone state of the CH_(3) bending mode.展开更多
In this paper,we study quantum dynamics of entanglement and single excitation transfer(SET) in an LH1-RC-type trimer which can describe a basic unit cell in the LH1-RC complex in the photosynthetic process.It is shown...In this paper,we study quantum dynamics of entanglement and single excitation transfer(SET) in an LH1-RC-type trimer which can describe a basic unit cell in the LH1-RC complex in the photosynthetic process.It is shown that there exists a sudden change of entanglement at the critic point of quantum phase transition(QPT) of the system at low temperatures,the entanglement sudden change caused by the QPT is suppressed at higher temperatures.We investigate the influence of environment on entanglement and SET.We show the generation of the dephasing-assisted entanglement between a donor and an acceptor and the existence of the steady-state entanglement,and demonstrate the entanglement transfer from donor-donor entanglement to donor-acceptor entanglement in the dynamic evolution.We reveal the close relation between the SET probability and donor-acceptor entanglement.Especially,we find that the SET probability is proportional to the amount of donor-acceptor entanglement under certain conditions.展开更多
We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on ...We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on impurity atoms. It is found that the nonclassicality of MQSSs can be manipulated by changing the number of the impurities and their interaction with the BEC. It is shown that the BEC matter-wave field exhibits a collapse and revival phenomenon which reveals the quantum nature of the BEC matter-wave field. We investigate the micro-macro entanglement between the impurities and the BEC, and find enhancement of the micro-macro entanglement induced by the initial quantum coherence of the impurity atoms.展开更多
The integral cross sections and rate constants of pure rotational and ro-vibrational energy transfer processes for the Ar-HF system are thoroughly studied by using the timeindependent close coupling method based on ou...The integral cross sections and rate constants of pure rotational and ro-vibrational energy transfer processes for the Ar-HF system are thoroughly studied by using the timeindependent close coupling method based on our newly constructed potential energy surface. Compared to previous theoretical results, pure rotational transitions in this work achieve better agreement with the experimental data. For ro-vibrational energy transfer, it is found that quasi-resonant transitions dominate the cross sections in all cases. Furthermore, the vibrational-resolved rate constant of transition v=1→v=0 increases very quickly with the temperature from 100K to 1500K and is also in good agreement with the available experimental results.展开更多
We consider a simple collinear collision ofa 'classical' particle with a harmonic oscillator within quantum semiclassical model and full quantum dynamics model, in which the latter is solved analytically in sq...We consider a simple collinear collision ofa 'classical' particle with a harmonic oscillator within quantum semiclassical model and full quantum dynamics model, in which the latter is solved analytically in squeezed state and exact diagonalization methods and acts as the exact solution of such a system. A comparison of these two models for different mass ratios between the 'classical' particle and the quantum particle is done, which gives a criterion when using the quantum-semiclassical model.展开更多
The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a...The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a recently developed ab initio-based globally accurate potential energy surface by the time-dependent wave packet approach under a reduceddimensional model.This reaction behaves like a barrier-less reaction at low collision energies and like an activated reaction with a well-defined barrier at high collision energies.Exciting either the symmetric or antisymmetric stretching mode of the molecule H_(2)S enhances the reactivity more than exciting the bending mode,which is rationalized by the coupling strength of each normal mode with the reaction coordinate.In addition,the modespecific rate constant shows a remarkable non-Arrhenius temperature dependence.展开更多
Quantum state-to-state dynamics of the N(4S) + H-2(X1+Σ) → NH(X3Σ) + H(2S) reaction is reported in an accurate novel potential energy surface constructed by Zhai et al.(2011 J. Chem. Phys. 135 104314). The time-dep...Quantum state-to-state dynamics of the N(4S) + H-2(X1+Σ) → NH(X3Σ) + H(2S) reaction is reported in an accurate novel potential energy surface constructed by Zhai et al.(2011 J. Chem. Phys. 135 104314). The time-dependent wave packet method, which is implemented on graphics processing units, is used to calculate the differential cross sections. The influences of the collision energy on the product state-resolved integral cross sections and total differential cross sections are calculated and discussed. It is found that the products NH are predominated by the backward scattering due to the small impact parameter collisions, with only minor components being forward and sideways scattered, and have an inverted rotational distribution and no inversion in vibrational distributions; both rebound and stripping mechanisms exist in the case of high collision energies.展开更多
We study the non-Markovian dynamics of an open quantum system with machine learning.The observable physical quantities and their evolutions are generated by using the neural network.After the pre-training is completed...We study the non-Markovian dynamics of an open quantum system with machine learning.The observable physical quantities and their evolutions are generated by using the neural network.After the pre-training is completed,we fix the weights in the subsequent processes thus do not need the further gradient feedback.We find that the dynamical properties of physical quantities obtained by the dynamical learning are better than those obtained by the learning of Hamiltonian and time evolution operator.The dynamical learning can be applied to other quantum many-body systems,non-equilibrium statistics and random processes.展开更多
The reactive collisions of nitrogen ion with hydrogen and its isotopic variations have great significance in the field of astrophysics.Herein,the state-to-state quantum time-dependent wave packet calculations of N^(+)...The reactive collisions of nitrogen ion with hydrogen and its isotopic variations have great significance in the field of astrophysics.Herein,the state-to-state quantum time-dependent wave packet calculations of N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction are carried out based on the recently developed potential energy surface[Phys.Chem.Chem.Phys.2122203(2019)].The integral cross sections(ICSs)and rate coefficients of both channels are precisely determined at the state-to-state level.The results of total ICSs and rate coefficients present a dramatic preference on the ND+product over the NH^(+)product,conforming to the long-lived complex-forming mechanism.Product state-resolved ICSs indicate that both the product molecules are difficult to excite to higher vibrational states,and the ND^(+)product has a hotter rotational state distribution.Moreover,the integral cross sections and rate coefficients are precisely determined at the state-to-state level and insights are provided about the differences between the two channels.The present results would provide an important reference for the further experimental studies at the finer level for this interstellar chemical reaction.The datasets presented in this paper,including the ICSs and rate coefficients of the two products for the title reaction,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00034.展开更多
According to a novel electronic ground-state potential energy surface of H2O^＋（X^4 A″）,we calculate the reaction probabilities and the integral cross section for the titled reaction O^＋＋ D2→OD^＋＋ D by the Che...According to a novel electronic ground-state potential energy surface of H2O^＋（X^4 A″）,we calculate the reaction probabilities and the integral cross section for the titled reaction O^＋＋ D2→OD^＋＋ D by the Chebyshev wave packet propagation method.The reaction probabilities in a collision-energy range of 0.0 e V–1.0 e V show an oscillatory structure for the O^＋＋ D2 reaction due to the existence of the potential well.Compared with the results of Martinez et al.,the present integral cross section is large,which is in line with experimental data.展开更多
文摘The ability to accurately simulate the time evolu-tion of quantum systems stands as a cornerstone of modern molecular science.It provides the essential mechanistic bridge between a system’s microscopic structure and its macroscopic function,a challenge first envisioned by Feynman.The central difficulty,and the unifying theme of this Special Topic,is the problem of“complexity”:a multifaceted challenge arising from the interplay of strongly coupled electronic and vibrational degrees of freedom,quantum statistics,and the non-trivial,often non-Markovian,memory effects exerted by a surrounding environment.
基金supported by the National Natural Science Foundation of China(No.22273005 and No.22422301)the Innovation Program for Quantum Science and Technology(No.2023ZD0300200)+1 种基金the National Security Academic Foundation(No.U2330201)the Fundamental Research Funds for the Central Universities.
文摘Static disorder plays a crucial role in the electronic dynamics and spec-troscopy of complex molecular sys-tems.Traditionally,obtaining ob-servables averaged over static disor-der requires thousands of realiza-tions via direct sampling of the dis-order distribution,leading to high computational costs.In this work,we extend the auxiliary degree-of-freedom based matrix product state(MPS)method to handle system-bath correlated thermal equilibrium initial states,which can capture static disorder effects using a one-shot quantum dynamical simulation.We validate the effectiveness of the extended method by computing the dipole-dipole time correlation function of the Holstein model relevant to the emission spectrum of molecular aggregates.Our results show that the one-shot method is very accu-rate with only a moderate increase in MPS bond dimension,thereby significantly reducing computational cost.Moreover,it enables the generation of a much larger number of samples than the conventional direct sampling method at negligible additional cost,thus reducing sta-tistical errors.This method provides a broadly useful tool for calculating equilibrium time cor-relation functions in system-bath coupled models with static disorder.
基金supported by the National Key R&D Program of China(No.2018YFE0203003)the National Natural Science Foundation of China(Nos.22173101,22173099,22288201,21703242)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0970203)the Innovation Program for Quantum Science and Technology(No.2021ZD0303305)Dalian Talents Innovation Support Program(No.2021RD05)the Open Fund(SKLMRD-K202508)of the State Key Laboratory of Molecular Reaction Dynamics in Dalian Institute of Chemical Physics,Chinese Academy of Sciences.The computational resources are supported by SongShan Lake HPC Center(SSL-HPC)in Great Bay University.
文摘In this study,six-dimensional(6D)time-dependent wave packet calcula-tions were employed to investigate the dissociation of HCl molecules on two bimetallic surfaces,Cu/Ag(111)and Cu/Au(111).These calculations were based on two accurate potential energy surfaces(PESs)constructed using neu-ral network methodology.Density functional theory(DFT)calculations revealed that the static barrier heights for HCl on Cu/Ag(111)and Cu/Au(111)were 0.32 eV and 0.28 eV,respectively.These values are significantly lower than the barrier height on pure Cu(111)(0.52 eV),primarily due to surface strain effects.However,it was found that the 6D dissociation probability of HCl in(v=0,1,j=0)states on Cu/Au(111)was considerably lower,despite its barrier height being 0.04 eV lower than that for Cu/Ag(111).The underlying mechanism for this observation was attributed to the non-monotonic dependence of the minimum energy path(MEP)on the molecular orientation,which was induced by charge transfer effect for HCl+Cu/Au(111).In contrast,HCl+Cu/Ag(111)exhibited a monotonic dependence.These contrasting behaviors led to dis-tinct differences in rotational alignment and excitation effects for the two reactions.
文摘The wave function temporal evolution on the one-dimensional （ID） lattice is considered in the tight-binding approxi- mation. The lattice consists of N equal sites and one impurity site （donor）. The donor differs from other lattice sites by the on-site electron energy E and the intersite coupling C. The moving wave packet is formed from the wave function initially localized on the donor. The exact solution for the wave packet velocity and the shape is derived at different values E and C. The velocity has the maximal possible group velocity v = 2. The wave packet width grows with time -t1/3 and its amplitude decreases ,- t-1/3. The wave packet reflects multiply from the lattice ends. Analytical expressions for the wave packet front propagation and recurrence are in good agreement with numeric simulations.
基金supported by the National Natural Science Foundation of China(Grant Nos.11074151 and 11304185)
文摘Quantum dynamics calculations for the title reaction H（2S） ＋ S2（X3∑g） → SH（X2П） ＋S（3P） are performed byusing a globally accurate double many-body expansion potential energy surface [J. Phys. Chem. A 115 5274 （2011）]. The Chebyshev real wave packet propagation method is employed to obtain the dynamical information, such as reaction probability, initial state-specified integral cross section, and thermal rate constant. It is found not only that there is a reaction threshold near 0.7 eV in both reaction probabilities and integral cross section curves, but also that both the probability and cross section increase firstly and then decrease as the collision energy increases. The existence of the resonance structure in both the probability and cross section curves is ascribed to the deep potential well. The calculation of the rate constant reveals that the reaction occurring on the potential energy surface of the ground-state HS2 is slow to take place.
文摘In this work, we discuss the topological transformation of quantum dynamics by showing the wave dynamics of a quantum particle on different types of topological structures in various dimensions from the fundamental polygons of the corresponding universal covering spaces. This is not the view from different perspectives of an observer who simply uses different coordinate systems to describe the same physical phenomenon but rather possible geometric and topological structures that quantum particles are endowed with when they are identified with differentiable manifolds that are embedded or immersed in Euclidean spaces of higher dimension. We present our discussions in the form of Bohr model in one, two and three dimensions using linear wave equations. In one dimension, the fundamental polygon is an interval and the universal covering space is the straight line and in this case the standing wave on a finite string is transformed into the standing wave on a circle which can be applied into the Bohr model of the hydrogen atom. In two dimensions, the fundamental polygon is a square and the universal covering space is the plane and in this case, the standing wave on the square is transformed into the standing wave on different surfaces that can be formed by gluing opposite sides of the square, which include a 2-sphere, a 2-torus, a Klein bottle and a projective plane. In three dimensions, the fundamental polygon is a cube and the universal covering space is the three-dimensional Euclidean space. It is shown that a 3-torus and the manifold K?× S1?defined as the product of a Klein bottle and a circle can be constructed by gluing opposite faces of a cube. Therefore, in three-dimensions, the standing wave on a cube is transformed into the standing wave on a 3-torus or on the manifold K?× S1. We also suggest that the mathematical degeneracy may play an important role in quantum dynamics and be associated with the concept of wavefunction collapse in quantum mechanics.
基金supported by the National Natural Sci-ence Foundation of China(No.21973098 and No.22133003)the Beijing National Laboratory for Molecular SciencesJianwei Cao acknowledges the Youth Innovation Promotion Association CAS(No.2018045).
文摘We present a quantum dynamics study on the isotope effects of hydro-gen transfer isomerization in the formic acid dimer,and this is achieved by multidimensional dy-namics calculations with an efficient quantum mechanical theoretical scheme developed by our group,on a full-dimensional neural network ab initio potential energy surface.The ground-state and fundamental tun-neling splittings for four deuterium isotopologues of formic acid dimer are considered,and the calculated results are in very good general agreement with the avail-able experimental measurements.Strong isotope effects are revealed,the mode-specific funda-mental excitation effects on the tunneling rate are evidently influenced by the deuterium sub-stitution of H atom with the substitution on the OH bond being more effective than on the CH bond.Our studies are helpful for acquiring a better understanding of isotope effects in the double-hydrogen transfer processes.
基金Supported by the National Natural Science Foundation of China under Grant No.10771208the Science Fund for Creative Research Groups under Grant No.10721101the Key Lab of Random Complex Structures and Data Science,CAS,under Grant No.2008DP173182
文摘The unified bound on the fundamental limit of quantum dynamics rate, as quietly recently obtainedby Levitin and Toffoli [Phys.Rev.Lett.103 (2009) 160502], is improved and refined.The improvement may bearbitrarily large in certain cases.In particular, this puts a limit on the operation rate of quantum gates allowed byquantum mechanics.
基金supported by the National Natural Science Foundation of China(No.21973098 and No.22133003)the Youth Innovation Promotion Association CAS(No.2018045)the Beijing National Laboratory for Molecular Sciences。
文摘We perform accurate quantum dynamcs calculations on the isomerization of vinylidene-acetylene.Large-scale parallel computations are accomplished by an efficient theoretical scheme developed by our group,in which the basis functions are customized for the double-H transfer process.The A_(1)' and B_(2)'' vinylidene and delocalization states are obtained.The peaks recently observed in the cryo-SEVI spectra are analyzed,and very good agreement for the energy levels is achieved between theory and experiment.The discrepancies of energy levels between our calculations and recent experimental cryo-SEVI spectra are of similar magnitudes to the experimental error bars,or≤30 cm^(-1) excluding those involving the excitation of the CCH_(2) scissor mode.A kind of special state,called the isomerization state,is revealed and reported,which is characterized by large probability densities in both vinylidene and acetylene regions.In addition,several states dominated by vinylidene character are reported for the first time.The present work would contribute to the understanding of the double-H transfer.
基金supported by the National Natural Science Foundation of China(No.22073089 and No.22033007)。
文摘Six-dimensional quantum dynamics calculations for the state-to-state scattering of H_(2)/D_(2) on the rigid Cu(100)surface have been carried out using a time-dependent wave packet approach,based on an accurate neural network potential energy surface fit for thousands of density functional theory data computed with the opt PBE-vd W density functional.The present results are compared with previous theoretical and experimental ones regarding to the rovibrationally(in)elastic scattering of H_(2) and D_(2) from Cu(100).In particular,we test the validity of the site-averaging approximation in this system by which the six-dimensional(in)elastic scattering probabilities are compared with the weighted average of four-dimensional results over fifteen fixed sites.Specifically,the site-averaging model reproduces vibrationally elastic scattering probabilities quite well,though less well for vibrationally inelastic results at high energies.These results support the use of the site-averaging model to reduce computational costs in future investigations on the state-to-state scattering dynamics of heavy diatomic or polyatomic molecules from metal surfaces,where full-dimensional calculations are too expensive.
基金supported by the National Natural Science Foundation of China(No.21773297,No.21973108,and No.21921004 to Minghui Yang,No.21973109 to Hongwei Song)。
文摘The mode selectivity of the H+CH_(3)D→H_(2)+CH_(2)D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method.The reaction dynamics are studied for the reactant CH_(3)D initially from the ground state,the CH_(3) symmetry and asymmetry stretching excitation,the CD stretching excitation and the fundamental and the first overtone of the CH_(3) bending mode.The calculated reaction probabilities show that exciting either of the CH_(3) stretching modes enhances the reactivity in the collision energy range below 1.0 eV,while the CD stretching excitation does not obviously prompt the reaction.Fundamental CH_(3) bending excitation has nearly no effect on promoting reactivity.However,a significant enhancement is observed for the first overtone excitation of the CH_(3) bending mode,resulting from the Fermi resonance between the fundamental state of the CH_(3) symmetry stretching mode and the first overtone state of the CH_(3) bending mode.
基金Supported by the National Fundamental Research Program under Grant No.2007CB925204the National Natural Science Foundation under Grant Nos.10775048 and 11075050+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT0964Hunan Provincial Natural Science Foundation under Grant No.11JJ7001
文摘In this paper,we study quantum dynamics of entanglement and single excitation transfer(SET) in an LH1-RC-type trimer which can describe a basic unit cell in the LH1-RC complex in the photosynthetic process.It is shown that there exists a sudden change of entanglement at the critic point of quantum phase transition(QPT) of the system at low temperatures,the entanglement sudden change caused by the QPT is suppressed at higher temperatures.We investigate the influence of environment on entanglement and SET.We show the generation of the dephasing-assisted entanglement between a donor and an acceptor and the existence of the steady-state entanglement,and demonstrate the entanglement transfer from donor-donor entanglement to donor-acceptor entanglement in the dynamic evolution.We reveal the close relation between the SET probability and donor-acceptor entanglement.Especially,we find that the SET probability is proportional to the amount of donor-acceptor entanglement under certain conditions.
基金supported by the National Natural Science Foundation of China under Grants No. 11775075No.1143011 and No. 11935006。
文摘We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on impurity atoms. It is found that the nonclassicality of MQSSs can be manipulated by changing the number of the impurities and their interaction with the BEC. It is shown that the BEC matter-wave field exhibits a collapse and revival phenomenon which reveals the quantum nature of the BEC matter-wave field. We investigate the micro-macro entanglement between the impurities and the BEC, and find enhancement of the micro-macro entanglement induced by the initial quantum coherence of the impurity atoms.
基金supported by the National Natural Science Foundation of China (No.21590802 and No.21733006)
文摘The integral cross sections and rate constants of pure rotational and ro-vibrational energy transfer processes for the Ar-HF system are thoroughly studied by using the timeindependent close coupling method based on our newly constructed potential energy surface. Compared to previous theoretical results, pure rotational transitions in this work achieve better agreement with the experimental data. For ro-vibrational energy transfer, it is found that quasi-resonant transitions dominate the cross sections in all cases. Furthermore, the vibrational-resolved rate constant of transition v=1→v=0 increases very quickly with the temperature from 100K to 1500K and is also in good agreement with the available experimental results.
文摘We consider a simple collinear collision ofa 'classical' particle with a harmonic oscillator within quantum semiclassical model and full quantum dynamics model, in which the latter is solved analytically in squeezed state and exact diagonalization methods and acts as the exact solution of such a system. A comparison of these two models for different mass ratios between the 'classical' particle and the quantum particle is done, which gives a criterion when using the quantum-semiclassical model.
基金supported by the National Natural Science Foundation of China(No.21973109 to Hongwei Song,No.21773297,No.21973108,and No.21921004 to Minghui Yang)the Ministry of Education,Singapore,under its Academic Research Fund Tier 1(RG83/20)to Yunpeng Lu。
文摘The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a recently developed ab initio-based globally accurate potential energy surface by the time-dependent wave packet approach under a reduceddimensional model.This reaction behaves like a barrier-less reaction at low collision energies and like an activated reaction with a well-defined barrier at high collision energies.Exciting either the symmetric or antisymmetric stretching mode of the molecule H_(2)S enhances the reactivity more than exciting the bending mode,which is rationalized by the coupling strength of each normal mode with the reaction coordinate.In addition,the modespecific rate constant shows a remarkable non-Arrhenius temperature dependence.
基金supported by the National Natural Science Foundation of China(Grant No.11074151)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2014AM022)
文摘Quantum state-to-state dynamics of the N(4S) + H-2(X1+Σ) → NH(X3Σ) + H(2S) reaction is reported in an accurate novel potential energy surface constructed by Zhai et al.(2011 J. Chem. Phys. 135 104314). The time-dependent wave packet method, which is implemented on graphics processing units, is used to calculate the differential cross sections. The influences of the collision energy on the product state-resolved integral cross sections and total differential cross sections are calculated and discussed. It is found that the products NH are predominated by the backward scattering due to the small impact parameter collisions, with only minor components being forward and sideways scattered, and have an inverted rotational distribution and no inversion in vibrational distributions; both rebound and stripping mechanisms exist in the case of high collision energies.
基金the National Program for Basic Research of the Ministry of Science and Technology of China(Grant Nos.2016YFA0300600 and 2016YFA0302104)the National Natural Science Foundation of China(Grant Nos.12074410,12047502,11934015,11975183,11947301,11774397,11775178,and 11775177)+3 种基金the Major Basic Research Program of the Natural Science of Shaanxi Province,China(Grant No.2017ZDJC-32)the Australian Research Council(Grant No.DP 190101529)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)the Double First-Class University Construction Project of Northwest University.
文摘We study the non-Markovian dynamics of an open quantum system with machine learning.The observable physical quantities and their evolutions are generated by using the neural network.After the pre-training is completed,we fix the weights in the subsequent processes thus do not need the further gradient feedback.We find that the dynamical properties of physical quantities obtained by the dynamical learning are better than those obtained by the learning of Hamiltonian and time evolution operator.The dynamical learning can be applied to other quantum many-body systems,non-equilibrium statistics and random processes.
基金Project supported by the National Natural Science Foundation of China(Grant No.11774043).
文摘The reactive collisions of nitrogen ion with hydrogen and its isotopic variations have great significance in the field of astrophysics.Herein,the state-to-state quantum time-dependent wave packet calculations of N^(+)(3P)+HD→NH^(+)/ND^(+)+D/H reaction are carried out based on the recently developed potential energy surface[Phys.Chem.Chem.Phys.2122203(2019)].The integral cross sections(ICSs)and rate coefficients of both channels are precisely determined at the state-to-state level.The results of total ICSs and rate coefficients present a dramatic preference on the ND+product over the NH^(+)product,conforming to the long-lived complex-forming mechanism.Product state-resolved ICSs indicate that both the product molecules are difficult to excite to higher vibrational states,and the ND^(+)product has a hotter rotational state distribution.Moreover,the integral cross sections and rate coefficients are precisely determined at the state-to-state level and insights are provided about the differences between the two channels.The present results would provide an important reference for the further experimental studies at the finer level for this interstellar chemical reaction.The datasets presented in this paper,including the ICSs and rate coefficients of the two products for the title reaction,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00034.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674198 and 11304185)
文摘According to a novel electronic ground-state potential energy surface of H2O^＋（X^4 A″）,we calculate the reaction probabilities and the integral cross section for the titled reaction O^＋＋ D2→OD^＋＋ D by the Chebyshev wave packet propagation method.The reaction probabilities in a collision-energy range of 0.0 e V–1.0 e V show an oscillatory structure for the O^＋＋ D2 reaction due to the existence of the potential well.Compared with the results of Martinez et al.,the present integral cross section is large,which is in line with experimental data.
