A general method for an analytical calculation of SU(N)lattice gauge theories with finite N≥3 developed.As an example,the order parameter(E)of lattice SU(4)gauge systetn is calculated.The result is in good agree^nent...A general method for an analytical calculation of SU(N)lattice gauge theories with finite N≥3 developed.As an example,the order parameter(E)of lattice SU(4)gauge systetn is calculated.The result is in good agree^nent with Monte Carlo simulations.展开更多
Recently,a new method has been proposed to compute parton distributions using boosted correlators fixed in the Coulomb gauge(CG)within the framework of large-momentum effective theory.This approach,which does not invo...Recently,a new method has been proposed to compute parton distributions using boosted correlators fixed in the Coulomb gauge(CG)within the framework of large-momentum effective theory.This approach,which does not involve Wilson lines,could greatly improve the efficiency and precision of lattice quantum chromodynamics calculations.However,concerns remain regarding whether systematic uncertainties from Gribov copies,which correspond to ambiguities in lattice gauge-fixing,are adequately controlled.This work assesses the effects of Gribov copies on Coulomb-gauge-fixed quark correlators.We utilize different strategies for Coulomb-gauge fixing,selecting two different groups of Gribov copies based on lattice gauge configurations.We examine the differences in the resulting spatial quark correlators in both vacuum and pion states.Our findings indicate that the statistical errors of the matrix elements from both Gribov copies,regardless of the correlation range,decrease proportionally to the square root of the number of gauge configurations.The difference between the strategies does not show statistical significance compared to the gauge noise,demonstrating that the effect of the Gribov copies can be neglected in practical lattice calculations of quark parton distributions.展开更多
We have investigated the gauge dependence of physical observables in a quantum Rabi model under different potential fields arising from the Hilbert space truncation of the atomic degrees of freedom.In both the square-...We have investigated the gauge dependence of physical observables in a quantum Rabi model under different potential fields arising from the Hilbert space truncation of the atomic degrees of freedom.In both the square-well and harmonic potentials,the optimal gauge for the ground-state energy depends on the cavity frequency,which is optimal in the low-frequency limit,whereas the Coulomb gauge is optimal in the high-frequency limit.For a dynamic quantity,such as an out-of-time-order correlator,we have demonstrated the necessity of introducing an optimal dynamic gauge.This study provides deeper insight into the intricate relationship between gauge choice and the dynamics of quantum electrodynamics systems,resulting in more accurate theoretical frameworks.展开更多
Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined...Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined the experience of theoreticians and operators. The system applied the expression method of rule-skeleton+rule-body', and selected an appropriate non-exact reference model and self-study algorithm. The whole system, including auxiliary routes, is designed in Borland C++. Some experiments on this system have been done, and a good result has been achieved.展开更多
Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA ...Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.展开更多
An investigation is carried out for the violation of the strong energy condition by a generic field system consisting of charged scalar boson condensate,fermions,and U(1)gauge field.The Bose-Einstein condensation of t...An investigation is carried out for the violation of the strong energy condition by a generic field system consisting of charged scalar boson condensate,fermions,and U(1)gauge field.The Bose-Einstein condensation of the system is also studied by the Hamiltonian formulation.It is found that the strong energy condition can be violated by this quantum field system at high densities.展开更多
In terms of the Dirac's finite contact transformation,we derive the principle on the choice of gauge conditions in the general singular Lagrangian system.It is applied successfully to Cawley's first counter-ex...In terms of the Dirac's finite contact transformation,we derive the principle on the choice of gauge conditions in the general singular Lagrangian system.It is applied successfully to Cawley's first counter-example of Dirac's conjecture.The number of gauge conditions or gauge freedoms is given and it is shown to be different from the accustomed conclusion which is always equal to the number of all the first-class constraints.展开更多
Conservation law plays a very important role in many geometric variational problems and related elliptic systems.In this note,we refine the conservation law obtained by Lamm-Rivière for fourth order systems and d...Conservation law plays a very important role in many geometric variational problems and related elliptic systems.In this note,we refine the conservation law obtained by Lamm-Rivière for fourth order systems and de Longueville-Gastel for general even order systems.展开更多
Gauge field theory is a fundamental concept in modern physics,attracting many theoretical and experimental efforts towards its simulation.In this paper we propose that a simple model,in which fermions coupled to a dyn...Gauge field theory is a fundamental concept in modern physics,attracting many theoretical and experimental efforts towards its simulation.In this paper we propose that a simple model,in which fermions coupled to a dynamical lattice gauge field,can be engineered via the Floquet approach.The model possesses both an independent Maxwell term and local Z_(2) gauge symmetry.Our proposal relies on a species-dependent optical lattice,and can be achieved in one,two or three dimensions.By a unitary transformation,this model can be mapped into a non-interacting composite fermion system with fluctuating background charge.With the help of this composite fermion picture,two characteristic observations are predicted.One is radio-frequency spectroscopy,which exhibits no dispersion in all parameter regimes.The second is dynamical localization,which depends on the structure of the initial states.展开更多
Monopoles and vortices are well known magnetically charged soliton solutions of gauge field equations. Extending the idea of Dirac on monopoles, Schwinger pioneered the concept of solitons carrying both electric and m...Monopoles and vortices are well known magnetically charged soliton solutions of gauge field equations. Extending the idea of Dirac on monopoles, Schwinger pioneered the concept of solitons carrying both electric and magnetic charges, called dyons, which are useful in modeling elementary particles. Mathematically, the existence of dyons presents interesting variational partial differential equation problems, subject to topological constraints. This article is a survey on recent progress in the study of dyons.展开更多
The measurement accuracy of a wind tunnel balance is the key factor to improve the measurement accuracy for a test model in the wind tunnel. In order to improve the measurement accuracy of the wind tunnel balance, a g...The measurement accuracy of a wind tunnel balance is the key factor to improve the measurement accuracy for a test model in the wind tunnel. In order to improve the measurement accuracy of the wind tunnel balance, a great deal of investigation is carried out in China. This paper summarizes a program to improve the measurement accuracy of wind tunnel balances. In the program, the investigation is carried out in three aspects (1) designing a drag component of the balance in low interactions (2) choosing high quality foil strain gauges with temperature self-compensation (3) choosing the excellent gauges and mounting them meticulously. As an example, these research achievements are applied in a φ18 six component balance. The measurement accuracy of a GB-04 standard model in a transonic wind tunnel with the φ18 six component balance comes up to the advanced world standard.展开更多
With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of res...With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.展开更多
In this paper, the compatibility between the integral type gauge transformation and the additional symmetry of the constrained KP hierarchy is given. And the string-equation constraint in matrix models is also derived.
Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequ...Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequence of change of electrical resistance resulted from bending of wires in the longitudinal-strain-experiencing sensing element of the gauge,a phenomenon discussed in this paper theoretically as well as experimentally.This effect yields unwanted signals to blend with output piezoresistive signals and is not negligible,hence decreases measurement accuracy sizably if not properly handled.To overcome this drawback,a new type of manganin transverse piezoresistive gauge has been developed by authors of this paper,which can reduce the resistance increment to acceptable low level so as to effectively bring the adverse effect under control.展开更多
The standard model is a chiral gauge theory where the gauge fields couple to the right-hand and the left-hand fermions differently.The standard model is defined perturbatively and describes all elementary particles(ex...The standard model is a chiral gauge theory where the gauge fields couple to the right-hand and the left-hand fermions differently.The standard model is defined perturbatively and describes all elementary particles(except gravitons)very well.However,for a long time,we do not know if we can have a non-perturbative definition of the standard model as a Hamiltonian quantum mechanical theory.Here we propose a way to give a modified standard model(with 48 two-component Weyl fermions)a non-perturbative definition by embedding the modified standard model into an SO(10)chiral gauge theory.We show that the SO(10)chiral gauge theory can be put on a lattice(a 3D spatial lattice with a continuous time)if we allow fermions to interact.Such a non-perturbatively defined standard model is a Hamiltonian quantum theory with a finite-dimensional Hilbert space for a finite space volume.More generally,using the defining connection between gauge anomalies and the symmetry-protected topological orders,one can show that any truly anomaly-free chiral gauge theory can be non-perturbatively defined by putting it on a lattice in the same dimension.展开更多
Ionization of atoms in counter-rotating and co-rotating bicircular laser fields is studied using the S-matrix theory in both length and velocity gauges.We show that for both the bicircular fields,ionization rates are ...Ionization of atoms in counter-rotating and co-rotating bicircular laser fields is studied using the S-matrix theory in both length and velocity gauges.We show that for both the bicircular fields,ionization rates are enhanced when the two circularly polarized lights have comparable intensities.In addition,the curves of ionization rate versus the field amplitude ratio of the two colors for counter-rotating and co-rotating fields coincide with each other in the length gauge case at the total laser intensity 5×10^14 W/cm^2,which agrees with the experimental observation.Moreover,the degree of the coincidence between the ionization rate curves of the two bicircular fields decreases with the increasing field amplitude ratio and decreasing total laser intensity.With the help of the ADK theory,the above characteristics of the ionization rate curves can be well interpreted,which is related to the transition from the tunneling to multiphoton ionization mechanism.展开更多
We try to explicitly derive the Lorentz-gauge covariant Dirac equation, in terms of pseudo-orthonormal bases, on Rindler spacetime and to work out, with all the necessary coefficients, the respective closed-form solut...We try to explicitly derive the Lorentz-gauge covariant Dirac equation, in terms of pseudo-orthonormal bases, on Rindler spacetime and to work out, with all the necessary coefficients, the respective closed-form solutions, in both Dirac and Weyl representations.展开更多
We show that a class of spectral problems are related to the spectral problem of the Volterra lattice through a gauge transformation. The transformation is given. We hope that our discussion can draw attention to the ...We show that a class of spectral problems are related to the spectral problem of the Volterra lattice through a gauge transformation. The transformation is given. We hope that our discussion can draw attention to the study of gauge transformation theory of differential-difference integrable systems.展开更多
Bauer recently presented a formula for the ionization rate of a hydrogen atom in a strong linearly polarized laser field[J.Phys.B 49145601(2016)].He started from the Keldysh probability amplitude in the length gauge a...Bauer recently presented a formula for the ionization rate of a hydrogen atom in a strong linearly polarized laser field[J.Phys.B 49145601(2016)].He started from the Keldysh probability amplitude in the length gauge and utilized Reiss’s method in the velocity gauge.Instead,according to the Reiss probability amplitude in the velocity gauge and Keldysh’s derivation for the length gauge,we derive a formula for the ionization rate of a ground-state hydrogen atom or a hydrogenlike atom in a strong linearly polarized laser field.We compare the numerical results of the total ionization rate and the photoelectron energy distribution calculated from our formula with the results from Keldysh,Reiss,and Bauer.We find that the apparent discrepancies in the ionization rate are caused not only by different gauges,but also by different analytical methods used to derive the ionization rate.展开更多
基金Partially Supported by the National Natural Science Foundation of China。
文摘A general method for an analytical calculation of SU(N)lattice gauge theories with finite N≥3 developed.As an example,the order parameter(E)of lattice SU(4)gauge systetn is calculated.The result is in good agree^nent with Monte Carlo simulations.
基金supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics through Contract Nos. DE-AC02-06CH11357 and DE-SC0012704the frameworks of Scientific Discovery through Advanced Computing (SciDAC) award Fundamental Nuclear Physics at the Exascale and Beyond and the Quark-Gluon Tomography (QGT) Topical Collaboration, under contract No. DE-SC0023646partially supported by the 2023 Physical Sciences and Engineering (PSE) Early Investigator Named Award program at Argonne National Laboratory.
文摘Recently,a new method has been proposed to compute parton distributions using boosted correlators fixed in the Coulomb gauge(CG)within the framework of large-momentum effective theory.This approach,which does not involve Wilson lines,could greatly improve the efficiency and precision of lattice quantum chromodynamics calculations.However,concerns remain regarding whether systematic uncertainties from Gribov copies,which correspond to ambiguities in lattice gauge-fixing,are adequately controlled.This work assesses the effects of Gribov copies on Coulomb-gauge-fixed quark correlators.We utilize different strategies for Coulomb-gauge fixing,selecting two different groups of Gribov copies based on lattice gauge configurations.We examine the differences in the resulting spatial quark correlators in both vacuum and pion states.Our findings indicate that the statistical errors of the matrix elements from both Gribov copies,regardless of the correlation range,decrease proportionally to the square root of the number of gauge configurations.The difference between the strategies does not show statistical significance compared to the gauge noise,demonstrating that the effect of the Gribov copies can be neglected in practical lattice calculations of quark parton distributions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174194 and 12475033)the Fundamental Research Funds for the Central Universities。
文摘We have investigated the gauge dependence of physical observables in a quantum Rabi model under different potential fields arising from the Hilbert space truncation of the atomic degrees of freedom.In both the square-well and harmonic potentials,the optimal gauge for the ground-state energy depends on the cavity frequency,which is optimal in the low-frequency limit,whereas the Coulomb gauge is optimal in the high-frequency limit.For a dynamic quantity,such as an out-of-time-order correlator,we have demonstrated the necessity of introducing an optimal dynamic gauge.This study provides deeper insight into the intricate relationship between gauge choice and the dynamics of quantum electrodynamics systems,resulting in more accurate theoretical frameworks.
文摘Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined the experience of theoreticians and operators. The system applied the expression method of rule-skeleton+rule-body', and selected an appropriate non-exact reference model and self-study algorithm. The whole system, including auxiliary routes, is designed in Borland C++. Some experiments on this system have been done, and a good result has been achieved.
基金funded by National Magnetic Confinement Fusion Science Program of China under Contract No.2013GB114004,No.2014GB106005 & No.2015GB101000National Nature Science Foundation of China under Contract No.11625524,No.11321092 and No.11405210partly supported by the Japan Society for the Promotion of ScienceNational Research Foundation of Korea-National Science Foundation of China(JSPS-NRF-NSFC) A3 Foresight Program in the field of Plasma Physics(NSFC No.11261140328)
文摘Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.
基金Supported by the National Natural Science Foundation of China under Grant No.19773013the Chinese Academy of Sciences under Grant No.KJ952-J1-352.
文摘An investigation is carried out for the violation of the strong energy condition by a generic field system consisting of charged scalar boson condensate,fermions,and U(1)gauge field.The Bose-Einstein condensation of the system is also studied by the Hamiltonian formulation.It is found that the strong energy condition can be violated by this quantum field system at high densities.
基金Supported by the National Natural Science Foundation of ChinaDoctoral Programme Foundation of the Institution of Higher Education of ChinaGrant LWTZ-1298 of the Chinese Academy of Sciences.
文摘In terms of the Dirac's finite contact transformation,we derive the principle on the choice of gauge conditions in the general singular Lagrangian system.It is applied successfully to Cawley's first counter-example of Dirac's conjecture.The number of gauge conditions or gauge freedoms is given and it is shown to be different from the accustomed conclusion which is always equal to the number of all the first-class constraints.
基金supported by the Young Scientist Program of the Ministry of Science and Technology of China(2021YFA1002200)the National Natural Science Foundation of China(12101362)+4 种基金the Natural Science Foundation of Shandong Province(ZR2021QA003)supported by the National Natural Science Foundation of China(12271296)the Natural Science Foundation of Hubei Province(2024AFA061)supported by the National Natural Science Foundation of China(11571131)the Open Research Fund of Key Laboratory of Nonlinear Analysis&Applications(Central China Normal University),Ministry of Education,P.R.China。
文摘Conservation law plays a very important role in many geometric variational problems and related elliptic systems.In this note,we refine the conservation law obtained by Lamm-Rivière for fourth order systems and de Longueville-Gastel for general even order systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.GG2030007011(WZ),GG203004045(WZ),12374477(PZ))Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302004(WZ))。
文摘Gauge field theory is a fundamental concept in modern physics,attracting many theoretical and experimental efforts towards its simulation.In this paper we propose that a simple model,in which fermions coupled to a dynamical lattice gauge field,can be engineered via the Floquet approach.The model possesses both an independent Maxwell term and local Z_(2) gauge symmetry.Our proposal relies on a species-dependent optical lattice,and can be achieved in one,two or three dimensions.By a unitary transformation,this model can be mapped into a non-interacting composite fermion system with fluctuating background charge.With the help of this composite fermion picture,two characteristic observations are predicted.One is radio-frequency spectroscopy,which exhibits no dispersion in all parameter regimes.The second is dynamical localization,which depends on the structure of the initial states.
文摘Monopoles and vortices are well known magnetically charged soliton solutions of gauge field equations. Extending the idea of Dirac on monopoles, Schwinger pioneered the concept of solitons carrying both electric and magnetic charges, called dyons, which are useful in modeling elementary particles. Mathematically, the existence of dyons presents interesting variational partial differential equation problems, subject to topological constraints. This article is a survey on recent progress in the study of dyons.
文摘The measurement accuracy of a wind tunnel balance is the key factor to improve the measurement accuracy for a test model in the wind tunnel. In order to improve the measurement accuracy of the wind tunnel balance, a great deal of investigation is carried out in China. This paper summarizes a program to improve the measurement accuracy of wind tunnel balances. In the program, the investigation is carried out in three aspects (1) designing a drag component of the balance in low interactions (2) choosing high quality foil strain gauges with temperature self-compensation (3) choosing the excellent gauges and mounting them meticulously. As an example, these research achievements are applied in a φ18 six component balance. The measurement accuracy of a GB-04 standard model in a transonic wind tunnel with the φ18 six component balance comes up to the advanced world standard.
基金Science Foundation of China University of Petroleum, Beijing (No.YJRC-2011-02)for the financial support during this research
文摘With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.
基金supported by the Fundamental Research Funds for the Central Universities(2015QNA43)
文摘In this paper, the compatibility between the integral type gauge transformation and the additional symmetry of the constrained KP hierarchy is given. And the string-equation constraint in matrix models is also derived.
基金Sponsored by the National Natural Science of China(10472014)
文摘Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequence of change of electrical resistance resulted from bending of wires in the longitudinal-strain-experiencing sensing element of the gauge,a phenomenon discussed in this paper theoretically as well as experimentally.This effect yields unwanted signals to blend with output piezoresistive signals and is not negligible,hence decreases measurement accuracy sizably if not properly handled.To overcome this drawback,a new type of manganin transverse piezoresistive gauge has been developed by authors of this paper,which can reduce the resistance increment to acceptable low level so as to effectively bring the adverse effect under control.
基金This research is supported by NSF Grant No.DMR-1005541,NSFC 11074140,and NSFC 11274192。
文摘The standard model is a chiral gauge theory where the gauge fields couple to the right-hand and the left-hand fermions differently.The standard model is defined perturbatively and describes all elementary particles(except gravitons)very well.However,for a long time,we do not know if we can have a non-perturbative definition of the standard model as a Hamiltonian quantum mechanical theory.Here we propose a way to give a modified standard model(with 48 two-component Weyl fermions)a non-perturbative definition by embedding the modified standard model into an SO(10)chiral gauge theory.We show that the SO(10)chiral gauge theory can be put on a lattice(a 3D spatial lattice with a continuous time)if we allow fermions to interact.Such a non-perturbatively defined standard model is a Hamiltonian quantum theory with a finite-dimensional Hilbert space for a finite space volume.More generally,using the defining connection between gauge anomalies and the symmetry-protected topological orders,one can show that any truly anomaly-free chiral gauge theory can be non-perturbatively defined by putting it on a lattice in the same dimension.
基金Project supported by the Key Laboratory Project of Computational Physics of National Defense Science and Technology of China(Grant No.6142A05180401)the National Key Program for S&T Research and Development of China(Grant Nos.2019YFA0307700 and 2016YFA0401100)the National Natural Science Foundation of China(Grant Nos.11847307,11425414,11504215,11774361,and 11874246).
文摘Ionization of atoms in counter-rotating and co-rotating bicircular laser fields is studied using the S-matrix theory in both length and velocity gauges.We show that for both the bicircular fields,ionization rates are enhanced when the two circularly polarized lights have comparable intensities.In addition,the curves of ionization rate versus the field amplitude ratio of the two colors for counter-rotating and co-rotating fields coincide with each other in the length gauge case at the total laser intensity 5×10^14 W/cm^2,which agrees with the experimental observation.Moreover,the degree of the coincidence between the ionization rate curves of the two bicircular fields decreases with the increasing field amplitude ratio and decreasing total laser intensity.With the help of the ADK theory,the above characteristics of the ionization rate curves can be well interpreted,which is related to the transition from the tunneling to multiphoton ionization mechanism.
文摘We try to explicitly derive the Lorentz-gauge covariant Dirac equation, in terms of pseudo-orthonormal bases, on Rindler spacetime and to work out, with all the necessary coefficients, the respective closed-form solutions, in both Dirac and Weyl representations.
基金Supported by the National Natural Science Foundation of China under Grant No 11371241
文摘We show that a class of spectral problems are related to the spectral problem of the Volterra lattice through a gauge transformation. The transformation is given. We hope that our discussion can draw attention to the study of gauge transformation theory of differential-difference integrable systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274149 and 11304185)the Program of Shenyang Key Laboratory of Optoelectronic Materials and Technology,China(Grant No.F12-254-1-00)。
文摘Bauer recently presented a formula for the ionization rate of a hydrogen atom in a strong linearly polarized laser field[J.Phys.B 49145601(2016)].He started from the Keldysh probability amplitude in the length gauge and utilized Reiss’s method in the velocity gauge.Instead,according to the Reiss probability amplitude in the velocity gauge and Keldysh’s derivation for the length gauge,we derive a formula for the ionization rate of a ground-state hydrogen atom or a hydrogenlike atom in a strong linearly polarized laser field.We compare the numerical results of the total ionization rate and the photoelectron energy distribution calculated from our formula with the results from Keldysh,Reiss,and Bauer.We find that the apparent discrepancies in the ionization rate are caused not only by different gauges,but also by different analytical methods used to derive the ionization rate.
