Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spec...Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spectrum via excitation by a pair of XUV attosecond pulses and by a time-delayed mid-infrared(MIR)laser probe.Different from the scheme of the electronic excitation by a single XUV attosecond pulse,the application of a pair of XUV pulses provides extra degrees of freedom,such as the time delay and the intensity ratio between two XUV pulses,which make it possible to adjust the pump process,resulting in the modification of the ATA spectrum.We show that by varying the time delay between the two XUV pulses,the population of the dark state and the ATA spectrum of the laser-induced state have periodic modulations.We also demonstrate that the peak of the ATA spectrum of the laser-induced state appears at a fixed time delay between the XUV pair and the MIR laser when the intensity ratio is large,and it changes with the time delay when the intensity ratio is small,which can be related to either one of two peaks in the population of the dark state.展开更多
We investigate the light propagation dynamics in ultra-cold Rydberg medium with inverted-Y configuration based on the superatom theory.It is viable to store light information in two types of atomic spin coherence(triv...We investigate the light propagation dynamics in ultra-cold Rydberg medium with inverted-Y configuration based on the superatom theory.It is viable to store light information in two types of atomic spin coherence(trivial spin coherence and Rydberg spin coherence),which makes the system a prospective platform for versatile light manipulation.A normal feature is to realize efficient light storage with simultaneous resonant control fields applied.An intriguing feature is to split light into two beams with different intensities and statistical properties if the control fields are applied separately.The beam of light retrieved from the Rydberg spin coherence is severely attenuated and shows anti-bunching character accompanied by the cooperative optical nonlinearity.Moreover,generation and manipulation of beating signal are achievable by applying the non-resonant control fields.展开更多
In this study, we explore the concept of cosmological inflation within the framework of the f(T, T)theory of gravity, where f is a general function of the torsion scalar T and the trace T of the energy-momentum tensor...In this study, we explore the concept of cosmological inflation within the framework of the f(T, T)theory of gravity, where f is a general function of the torsion scalar T and the trace T of the energy-momentum tensor.It is assumed that the conditions of slow-roll inflation are applicable in f(T, T) gravity. To determine different observables related to inflation, such as the tensor-to-scalar ratio r, scalar spectral index ns, spectral index αs, and tensor spectral index nt, the Hubble slow-roll parameters are utilized for a particular model of f(T, T). Lastly, an assessment is carried out to determine the feasibility of the models by conducting a numerical analysis of the parameters. The findings indicate that it is feasible to achieve compatibility with the observational measurements of slow-roll parameters by utilizing different values of the free parameters.展开更多
Recent astronomical NASA observations indicates that visible matter contributes only to about 4% of the universe total energy density, meanwhile, dark matter and dark energy contributes to 26% and 70% of the universe ...Recent astronomical NASA observations indicates that visible matter contributes only to about 4% of the universe total energy density, meanwhile, dark matter and dark energy contributes to 26% and 70% of the universe total energy, respectively, with an average density close to 10–26 kg/m3. This paper proposes an equation of state of dark energy and dark matter as one unified entity. This equation is derived based on the ideal gas equation, Boltzmann constant, Einstein energy-mass principle and based on the assumption that dark energy and dark matter behave as a perfect fluid. This analysis presents what could be the most fundamental particle and quanta of dark matter and dark energy. Considering NASA’s Cosmic Microwave Background Explorer (CMB) which estimated that the sky has an average temperature close to 2.7251 Kelvin, then the equivalent mass and energy of the proposed fundamental particle is determined. It is found that this candidate particle has an equivalent mass of 4.2141 × 10–40 Kg which is equivalent to 3.7674 × 10–23 J. Surprisingly, this value has the same order of Boltzmann constant KB = 1.38 ×10–23 J/K. This candidate particle could be the most fundamental and lightest particle in Nature and serves as the basic block of matter (quarks and gluons). Moreover, assuming a uniform space dark energy/dark matter density, then the critical temperature at which the dark matter has a unity entity per volume is determined as 34.983 × 1012 K. Analytically, it proposes that at this trillion temperature scale, the dark matter particles unified into a new quark-hydron particle. Finally, tentative experimental verification can be con ducted using the Relativistic Heavy Ion Collider (RHIC).展开更多
This paper presents a novel physical interpretation of the state of matter of the quark-gluon as the most fundamental building blocks in nature. Such a model is derived based on the assumption that dark matter and dar...This paper presents a novel physical interpretation of the state of matter of the quark-gluon as the most fundamental building blocks in nature. Such a model is derived based on the assumption that dark matter and dark energy behave as a perfect ideal fluid at extremely high temperature. By the virtue of Boltzmann constant of the ideal gas law and NASA’s Cosmic Microwave Background Explorer (CMB) which estimate that the space has an average temperature close to 2.7251 Kelvin, then the equivalent mass-energy of the fundamental particle of the dark matter/dark energy is determined. Moreover, assuming a uniform space dark energy/dark matter density, then the critical temperature at which the dark matter has a unity entity per volume is identified as 64 × 1012 K. The calculated critical temperature of the quark-gluon plasma is found to be proportional to the temperature generated by colliding heavy ions at the Relativistic Heavy Ion Collider (RHIC) and European Organization for Nuclear Research (CERN). Moreover, the individual critical temperatures of the quark-gluon plasma matter at which the elements of the Periodic Table are generated are explicitly determined. The generation temperature trend of the elements of the Periodic Table groups and Periods is then demonstrated. Accordingly, the phase diagram of the quark-gluon state matter is proposed. Finally, a new model of quark-gluon power generation plant is proposed and aims to serve humanity with new energy sources in the new millennium.展开更多
We revisit a theoretical scheme to create quantum entanglement of two three-level superconducting quantuminterference devices (SQUIDs) with the help of an auxiliary SQUID.In this scenario,two three-level systems are c...We revisit a theoretical scheme to create quantum entanglement of two three-level superconducting quantuminterference devices (SQUIDs) with the help of an auxiliary SQUID.In this scenario,two three-level systems are coupledto a quantized cavity field and a classical external field and thus form dark states.The quantum entanglement can beproduced by a quantum measurement on the auxiliary SQUID.Our investigation emphasizes the quantum effect of theauxiliary SQUID.For the experimental feasibility and accessibility of the scheme,we calculate the time evolution of thewhole system including the auxiliary SQUID.To ensure the efficiency of generating quantum entanglement,relationsbetween the measurement time and dominate parameters of the system are analyzed according to detailed calculations.展开更多
Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,who...Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,whose scattering rate and recoil velocity are large.Two EOMs are used to compensate the rapidly changing Doppler shifts arised from the movement of molecules,and to cover the hyperfine energy structure of MgF,respectively.Based the scattering rate maps calculated from an optical Bloch equation model,individual molecule trajectories are simulated by using a semi-classical three-dimensional Monte Carlo approach.We show how the modulation configuration of EOM and the magnetic field influence the slowing results.The study shows that a cryogenic buffer gas-cooled MgF beam source is possible to be slowed down with a number of∼1.4×10^(6)–10^(7),and the final forward speed peaks at∼10 m/s near the capture velocity of a molecular MOT.展开更多
We report the experimental realization of dark state atoms trapping in a nanofiber optical lattice.By applying the magicwavelength trapping potentials of cesium atoms,the AC Stark shifts are strongly suppressed.The da...We report the experimental realization of dark state atoms trapping in a nanofiber optical lattice.By applying the magicwavelength trapping potentials of cesium atoms,the AC Stark shifts are strongly suppressed.The dark magneto-optical trap efficiently transfers the cold atoms from bright (6S_(1/2),F=4) into dark state (6S_(1/2),F=3) for hyperfine energy levels of cesium atoms.The observed transfer efficiency is as high as 98%via saturation measurement.The trapping lifetime of dark state atoms trapped by a nanofiber optical lattice is also investigated,which is the key element for realizing optical storage.This work contributes to the manipulation of atomic electric dipole spin waves and quantum information storage for fiber networks.展开更多
We utilize the topological-geometrical structure imposed by the Heterotic superstring theory on spacetime in conjunction with the K3 Kähler manifold to explain the mysterious nature of dark matter and its cou...We utilize the topological-geometrical structure imposed by the Heterotic superstring theory on spacetime in conjunction with the K3 Kähler manifold to explain the mysterious nature of dark matter and its coupling to the pure dark energy density of the cosmos. The analogous situations in the case of a Kerr black hole as well as the redundant components of the Riemannian tensor are pointed out and the final result was found to be in complete agreement with all previous theoretical ones as well as all recent accurate measurements and cosmic observations. We conclude by commenting briefly on the Cantorian model of Zitterbewegung and the connection between Olbers’s paradox and dark energy.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.91950102 and 11834004)the Natural Science Foundation of Jiangsu Province(Grant No.BK20220925)the Funding of Nanjing University of Science and Technology(NJUST)(Grant No.TSXK2022D005)
文摘Attosecond transient absorption(ATA)has been developed as an all-optical technique for probing electron dynamics in matter.Here we present a scheme that can modify the laserinduced state and the corresponding ATA spectrum via excitation by a pair of XUV attosecond pulses and by a time-delayed mid-infrared(MIR)laser probe.Different from the scheme of the electronic excitation by a single XUV attosecond pulse,the application of a pair of XUV pulses provides extra degrees of freedom,such as the time delay and the intensity ratio between two XUV pulses,which make it possible to adjust the pump process,resulting in the modification of the ATA spectrum.We show that by varying the time delay between the two XUV pulses,the population of the dark state and the ATA spectrum of the laser-induced state have periodic modulations.We also demonstrate that the peak of the ATA spectrum of the laser-induced state appears at a fixed time delay between the XUV pair and the MIR laser when the intensity ratio is large,and it changes with the time delay when the intensity ratio is small,which can be related to either one of two peaks in the population of the dark state.
基金Project supported by the National Natural Science Foundation of China(Grant No.12104107)the Natural Science Foundation of Guangxi Province,China(Grant No.AD19245180)+2 种基金the Natural Science Foundation of Jilin ProvinceChina(Grant No.20220101009JC)the“Yucai Project”of Guangxi Normal University。
文摘We investigate the light propagation dynamics in ultra-cold Rydberg medium with inverted-Y configuration based on the superatom theory.It is viable to store light information in two types of atomic spin coherence(trivial spin coherence and Rydberg spin coherence),which makes the system a prospective platform for versatile light manipulation.A normal feature is to realize efficient light storage with simultaneous resonant control fields applied.An intriguing feature is to split light into two beams with different intensities and statistical properties if the control fields are applied separately.The beam of light retrieved from the Rydberg spin coherence is severely attenuated and shows anti-bunching character accompanied by the cooperative optical nonlinearity.Moreover,generation and manipulation of beating signal are achievable by applying the non-resonant control fields.
基金the Science and Engineering Research Board,Department of Science and Technology,Government of India for financial support to carry out research project No.:CRG/2022/001847 and IUCAA。
文摘In this study, we explore the concept of cosmological inflation within the framework of the f(T, T)theory of gravity, where f is a general function of the torsion scalar T and the trace T of the energy-momentum tensor.It is assumed that the conditions of slow-roll inflation are applicable in f(T, T) gravity. To determine different observables related to inflation, such as the tensor-to-scalar ratio r, scalar spectral index ns, spectral index αs, and tensor spectral index nt, the Hubble slow-roll parameters are utilized for a particular model of f(T, T). Lastly, an assessment is carried out to determine the feasibility of the models by conducting a numerical analysis of the parameters. The findings indicate that it is feasible to achieve compatibility with the observational measurements of slow-roll parameters by utilizing different values of the free parameters.
文摘Recent astronomical NASA observations indicates that visible matter contributes only to about 4% of the universe total energy density, meanwhile, dark matter and dark energy contributes to 26% and 70% of the universe total energy, respectively, with an average density close to 10–26 kg/m3. This paper proposes an equation of state of dark energy and dark matter as one unified entity. This equation is derived based on the ideal gas equation, Boltzmann constant, Einstein energy-mass principle and based on the assumption that dark energy and dark matter behave as a perfect fluid. This analysis presents what could be the most fundamental particle and quanta of dark matter and dark energy. Considering NASA’s Cosmic Microwave Background Explorer (CMB) which estimated that the sky has an average temperature close to 2.7251 Kelvin, then the equivalent mass and energy of the proposed fundamental particle is determined. It is found that this candidate particle has an equivalent mass of 4.2141 × 10–40 Kg which is equivalent to 3.7674 × 10–23 J. Surprisingly, this value has the same order of Boltzmann constant KB = 1.38 ×10–23 J/K. This candidate particle could be the most fundamental and lightest particle in Nature and serves as the basic block of matter (quarks and gluons). Moreover, assuming a uniform space dark energy/dark matter density, then the critical temperature at which the dark matter has a unity entity per volume is determined as 34.983 × 1012 K. Analytically, it proposes that at this trillion temperature scale, the dark matter particles unified into a new quark-hydron particle. Finally, tentative experimental verification can be con ducted using the Relativistic Heavy Ion Collider (RHIC).
文摘This paper presents a novel physical interpretation of the state of matter of the quark-gluon as the most fundamental building blocks in nature. Such a model is derived based on the assumption that dark matter and dark energy behave as a perfect ideal fluid at extremely high temperature. By the virtue of Boltzmann constant of the ideal gas law and NASA’s Cosmic Microwave Background Explorer (CMB) which estimate that the space has an average temperature close to 2.7251 Kelvin, then the equivalent mass-energy of the fundamental particle of the dark matter/dark energy is determined. Moreover, assuming a uniform space dark energy/dark matter density, then the critical temperature at which the dark matter has a unity entity per volume is identified as 64 × 1012 K. The calculated critical temperature of the quark-gluon plasma is found to be proportional to the temperature generated by colliding heavy ions at the Relativistic Heavy Ion Collider (RHIC) and European Organization for Nuclear Research (CERN). Moreover, the individual critical temperatures of the quark-gluon plasma matter at which the elements of the Periodic Table are generated are explicitly determined. The generation temperature trend of the elements of the Periodic Table groups and Periods is then demonstrated. Accordingly, the phase diagram of the quark-gluon state matter is proposed. Finally, a new model of quark-gluon power generation plant is proposed and aims to serve humanity with new energy sources in the new millennium.
基金The project supported by National Natural Science Foundation of China under Grant No.10474104the National Fundamental Research Program of China under Grant No.2001CB309310
文摘We revisit a theoretical scheme to create quantum entanglement of two three-level superconducting quantuminterference devices (SQUIDs) with the help of an auxiliary SQUID.In this scenario,two three-level systems are coupledto a quantized cavity field and a classical external field and thus form dark states.The quantum entanglement can beproduced by a quantum measurement on the auxiliary SQUID.Our investigation emphasizes the quantum effect of theauxiliary SQUID.For the experimental feasibility and accessibility of the scheme,we calculate the time evolution of thewhole system including the auxiliary SQUID.To ensure the efficiency of generating quantum entanglement,relationsbetween the measurement time and dominate parameters of the system are analyzed according to detailed calculations.
基金supports are from the National Natural Science Foundation of China under Grant Nos.11834003,91836103,and 91536218.
文摘Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing.The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed,whose scattering rate and recoil velocity are large.Two EOMs are used to compensate the rapidly changing Doppler shifts arised from the movement of molecules,and to cover the hyperfine energy structure of MgF,respectively.Based the scattering rate maps calculated from an optical Bloch equation model,individual molecule trajectories are simulated by using a semi-classical three-dimensional Monte Carlo approach.We show how the modulation configuration of EOM and the magnetic field influence the slowing results.The study shows that a cryogenic buffer gas-cooled MgF beam source is possible to be slowed down with a number of∼1.4×10^(6)–10^(7),and the final forward speed peaks at∼10 m/s near the capture velocity of a molecular MOT.
基金This work was supported by the National Key Research and Development Program of China(No.2017YFA0304203)National Natural Science Foundation of China(Nos.6210031464,61875110,12034012,and 12074231)+4 种基金NSFC Project for Excellent Research Team(No.61121064)“1331 KSC”,PCSIRT(No.IRT_17R70)National Time Service Center(NTSC)of the Chinese Academy of Sciences(CAS)(No.2009DP173082)State Key Laboratory of Surface Physics,Fudan University(No.KF2020_01)111 Project(No.D18001).
文摘We report the experimental realization of dark state atoms trapping in a nanofiber optical lattice.By applying the magicwavelength trapping potentials of cesium atoms,the AC Stark shifts are strongly suppressed.The dark magneto-optical trap efficiently transfers the cold atoms from bright (6S_(1/2),F=4) into dark state (6S_(1/2),F=3) for hyperfine energy levels of cesium atoms.The observed transfer efficiency is as high as 98%via saturation measurement.The trapping lifetime of dark state atoms trapped by a nanofiber optical lattice is also investigated,which is the key element for realizing optical storage.This work contributes to the manipulation of atomic electric dipole spin waves and quantum information storage for fiber networks.
文摘We utilize the topological-geometrical structure imposed by the Heterotic superstring theory on spacetime in conjunction with the K3 Kähler manifold to explain the mysterious nature of dark matter and its coupling to the pure dark energy density of the cosmos. The analogous situations in the case of a Kerr black hole as well as the redundant components of the Riemannian tensor are pointed out and the final result was found to be in complete agreement with all previous theoretical ones as well as all recent accurate measurements and cosmic observations. We conclude by commenting briefly on the Cantorian model of Zitterbewegung and the connection between Olbers’s paradox and dark energy.
