The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Akitomo Tachibana - One of the best experts on this subject based on the ideXlab platform.
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Time-dependent renormalization of alpha-oscillators for QED
Journal of Mathematical Chemistry, 2016Co-Authors: Akitomo TachibanaAbstract:Time-dependent renormalization of QED (Quantum Electrodynamics) is performed in terms of sub-particles, b -photon, f -electron, $$f^{c}$$ f c -positron (see previous paper: Tachibana in J Math Chem 53:1943, 2015 ), which are called alpha-oscillators so named here in this paper. This is achieved by using q-number renormalization constants over and above alpha-resonance and thermalization of alpha-oscillators. This approach paves the way for realizing nonperturbationally space–time resolved simulation of the time-dependent QED Hamiltonian $$\hat{{H}}_{\mathrm{QED}} \left( t \right) $$ H ^ QED t .
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Computational Method for the Retarded Potential in the Real-Time Simulation of Quantum Electrodynamics
International Journal of Quantum Chemistry, 2016Co-Authors: Masahiro Fukuda, Kento Naito, Kazuhide Ichikawa, Akitomo TachibanaAbstract:We discuss the method to compute the integrals which appear in the retarded potential term for a real-time simulation based on QED (Quantum Electrodynamics). We show that the oscillatory integrals over the infinite interval involved in them can be efficiently performed by the method developed by Ooura and Mori based on the double exponential (DE) formula.
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Time-dependent renormalization of alpha-oscillators for QED
Journal of Mathematical Chemistry, 2016Co-Authors: Akitomo TachibanaAbstract:Time-dependent renormalization of QED (Quantum Electrodynamics) is performed in terms of sub-particles, b-photon, f-electron, \(f^{c}\)-positron (see previous paper: Tachibana in J Math Chem 53:1943, 2015), which are called alpha-oscillators so named here in this paper. This is achieved by using q-number renormalization constants over and above alpha-resonance and thermalization of alpha-oscillators. This approach paves the way for realizing nonperturbationally space–time resolved simulation of the time-dependent QED Hamiltonian \(\hat{{H}}_{\mathrm{QED}} \left( t \right) \).
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Study of Simulation Method of Time Evolution in Rigged QED
International Journal of Quantum Chemistry, 2012Co-Authors: Kazuhide Ichikawa, Masahiro Fukuda, Akitomo TachibanaAbstract:We discuss how we formulate time evolution of physical quantities in the framework of the Rigged QED (Quantum Electrodynamics). The Rigged QED is a theory which has been proposed to treat dynamics of electrons, photons and atomic nuclei in atomic and molecular systems in a Quantum field theoretic way. To solve the dynamics in the Rigged QED, we need different techniques from those developed for the conventional QED. As a first step toward this issue, we propose a procedure to expand the Dirac field operator, which represents electrons, by the electron annihilation/creation operators and solutions of the Dirac equation for electrons in nuclear potential. Similarly, the Schrodinger field operators, which represent atomic nuclei, are expanded by nucleus annihilation/creation operators. Then we derive time evolution equations for these annihilation and creation operators and discuss how time evolution of the operators for physical quantities can be calculated. In the end, we propose a method to approximate the evolution equations of the operators by the evolution equations for the density matrices of electrons and atomic nuclei. Under this approximation, we carry out numerical simulation of the time evolution of electron charge density of a hydrogen atom.
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a theoretical study on a reaction of iron iii hydroxide with boron trichloride by ab initio calculation
Journal of Molecular Structure-theochem, 2009Co-Authors: Kazuhide Ichikawa, Toshiyuki Myoraku, Akinori Fukushima, Yoshio Ishihara, Ryuichiro Isaki, Toshio Takeguchi, Akitomo TachibanaAbstract:Abstract We investigate a reaction of boron trichloride ( BCl 3 ) with iron(III) hydroxide ( Fe ( OH ) 3 ) by ab initio Quantum chemical calculation as a simple model for a reaction of iron impurities in BCl 3 gas. We also examine a reaction with water. We find that compounds such as Fe ( Cl ) ( OBCl 2 ) 2 ( OHBCl 2 ) and Fe ( Cl ) 2 ( OBCl 2 ) ( OHBCl 2 ) are formed while producing HCl and reaction paths to them are revealed. We also analyze the stabilization mechanism of these paths using newly-developed interaction energy density derived from electronic stress tensor in the framework of the Regional DFT (Density Functional Theory) and Rigged QED (Quantum Electrodynamics).
Hsien-hao Mei - One of the best experts on this subject based on the ideXlab platform.
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AXION SEARCH WITH Q & A EXPERIMENT
Modern Physics Letters A, 2010Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Dark matter is a focused issue in galactic evolution and cosmology. Axion is a viable particle candidate for dark matter. Its interaction with photon is an effective way to detect it, e.g., pseudoscalar-photon interaction will generate vacuum dichroism in a magnetic field. Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first give a brief historical account of planet hunting and dark matter evidence. We then review our 3.5 m Fabry-Perot interferometer together with our results of measuring vacuum dichroism and gaseous Cotton-Mouton effects. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass, at 2.3 T with 18,700 passes through a 0.6 m long magnet, for vacuum dichroism measurement. We are upgrading our interferometer to 7 m arm-length with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We aim at optical sensitivity with 532 nm cavity finesse around 100,000. When achieved, vacuum dichroism would be measured to 8.6 × 10-17 rad/pass in about 50 days, and QED birefringence would be measured to 28%.
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Axion Search with Q & A Experiment
Modern Physics Letters A, 2010Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Dark matter is a focused issue in galactic evolution and cosmology. Axion is a viable particle candidate for dark matter. Its interaction with photon is an effective way to detect it, e.g., pseudoscalar-photon interaction will generate vacuum dichroism in a magnetic field. Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first give a brief historical account of planet hunting and dark matter evidence. We then review our 3.5 m Fabry-Perot interferometer together with our results of measuring vacuum dichroism and gaseous Cotton-Mouton effects. Our first results give (-0.2 $\pm$ 2.8) $\times$ 10$^{-13}$ rad/pass, at 2.3 T with 18,700 passes through a 0.6 m long magnet, for vacuum dichroism measurement. We are upgrading our interferometer to 7 m arm-length with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We aim at 10 nrad/Hz$^{1/2}$ optical sensitivity with 532 nm cavity finesse around 100,000. When achieved, vacuum dichroism would be measured to 8.6 $\times$ 10$^{-17}$ rad/pass in about 50 days, and QED birefringence would be measured to 28 %.
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The status and prospects of the Q & A experiment with some applications
arXiv: Instrumentation and Detectors, 2009Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Motivated to measure the QED birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first review our 3.5 m Fabry-Perot interferometer together with our results of measuring Cotton-Mouton effects of gases. We are uprading our interferometer to 7 m armlength with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We will use 532 nm Nd:YAG laser as light source with cavity finesse around 100,000, and aim at 10 nrad/Hz^{1/2} optical sensitivity. With all these achieved and the upgrading of vacuum, QED birefringence would be measured to 28% in about 50 days. Along the way, we should be able to improve on the dichroism detection significantly.
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The status and prospects of the Q & A experi- ment with some applications
2009Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first review our 3.5 m Fabry-Perot interferometer together with our results of measuring Cotton-Mouton effects of gases. We are upgrading our interferometer to 7 m armlength with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We will use 532 nm Nd:YAG laser as light source with cavity finesse around 100,000, and aim at 10 nrad/Hz 1/2 optical sensitivity. With all these achieved and the upgrading of vacuum, QED birefringence would be measured to 28% in about 50 days. Along the way, we should be able to improve on the dichroism detection significantly.
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Q & A EXPERIMENT TO SEARCH FOR VACUUM DICHROISM, PSEUDOSCALAR-PHOTON INTERACTION AND MILLICHARGED FERMIONS
Modern Physics Letters A, 2007Co-Authors: Sheng-jui Chen, Hsien-hao MeiAbstract:A number of experiments are underway to detect vacuum birefringence and dichroism — PVLAS, Q & A, and BMV. Recently, PVLAS experiment has observed optical rotation in vacuum by a magnetic field (vacuum dichroism). Theoretical interpretations of this result include a possible pseudoscalar–photon interaction and the existence of millicharged fermions. Here, we report the progress and first results of Q & A (QED [Quantum Electrodynamics] and Axion) experiment proposed and started in 1994. We use a 3.5-m high-finesse (around 30,000) Fabry–Perot prototype detector extendable to 7-m with the cavity mirrors suspended using X-pendulum-double pendulums. To polarize the vacuum, we use a 2.3-T dipole permanent magnet rotated at 5–10 rev/s, with 27-mm-diameter clear borehole and 0.6-m field length. Our ellipsometer/polarization-rotation-detection-system is formed by a pair of Glan–Taylor type polarizing prisms with extinction ratio lower than 10-8 together with a polarization modulating Faraday Cell with/without a quarter wave plate. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass with 18,700 passes through a 2.3 T 0.6 m long magnet for vacuum dichroism measurement. We present our experimental limit on pseudo-scalar-photon interaction and millicharged fermions.
Sheng-jui Chen - One of the best experts on this subject based on the ideXlab platform.
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AXION SEARCH WITH Q & A EXPERIMENT
Modern Physics Letters A, 2010Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Dark matter is a focused issue in galactic evolution and cosmology. Axion is a viable particle candidate for dark matter. Its interaction with photon is an effective way to detect it, e.g., pseudoscalar-photon interaction will generate vacuum dichroism in a magnetic field. Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first give a brief historical account of planet hunting and dark matter evidence. We then review our 3.5 m Fabry-Perot interferometer together with our results of measuring vacuum dichroism and gaseous Cotton-Mouton effects. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass, at 2.3 T with 18,700 passes through a 0.6 m long magnet, for vacuum dichroism measurement. We are upgrading our interferometer to 7 m arm-length with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We aim at optical sensitivity with 532 nm cavity finesse around 100,000. When achieved, vacuum dichroism would be measured to 8.6 × 10-17 rad/pass in about 50 days, and QED birefringence would be measured to 28%.
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Axion Search with Q & A Experiment
Modern Physics Letters A, 2010Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Dark matter is a focused issue in galactic evolution and cosmology. Axion is a viable particle candidate for dark matter. Its interaction with photon is an effective way to detect it, e.g., pseudoscalar-photon interaction will generate vacuum dichroism in a magnetic field. Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first give a brief historical account of planet hunting and dark matter evidence. We then review our 3.5 m Fabry-Perot interferometer together with our results of measuring vacuum dichroism and gaseous Cotton-Mouton effects. Our first results give (-0.2 $\pm$ 2.8) $\times$ 10$^{-13}$ rad/pass, at 2.3 T with 18,700 passes through a 0.6 m long magnet, for vacuum dichroism measurement. We are upgrading our interferometer to 7 m arm-length with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We aim at 10 nrad/Hz$^{1/2}$ optical sensitivity with 532 nm cavity finesse around 100,000. When achieved, vacuum dichroism would be measured to 8.6 $\times$ 10$^{-17}$ rad/pass in about 50 days, and QED birefringence would be measured to 28 %.
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The status and prospects of the Q & A experiment with some applications
arXiv: Instrumentation and Detectors, 2009Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Motivated to measure the QED birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first review our 3.5 m Fabry-Perot interferometer together with our results of measuring Cotton-Mouton effects of gases. We are uprading our interferometer to 7 m armlength with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We will use 532 nm Nd:YAG laser as light source with cavity finesse around 100,000, and aim at 10 nrad/Hz^{1/2} optical sensitivity. With all these achieved and the upgrading of vacuum, QED birefringence would be measured to 28% in about 50 days. Along the way, we should be able to improve on the dichroism detection significantly.
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The status and prospects of the Q & A experi- ment with some applications
2009Co-Authors: Hsien-hao Mei, Sheng-jui Chen, Sheau-shi PanAbstract:Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first review our 3.5 m Fabry-Perot interferometer together with our results of measuring Cotton-Mouton effects of gases. We are upgrading our interferometer to 7 m armlength with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We will use 532 nm Nd:YAG laser as light source with cavity finesse around 100,000, and aim at 10 nrad/Hz 1/2 optical sensitivity. With all these achieved and the upgrading of vacuum, QED birefringence would be measured to 28% in about 50 days. Along the way, we should be able to improve on the dichroism detection significantly.
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Q & A EXPERIMENT TO SEARCH FOR VACUUM DICHROISM, PSEUDOSCALAR-PHOTON INTERACTION AND MILLICHARGED FERMIONS
Modern Physics Letters A, 2007Co-Authors: Sheng-jui Chen, Hsien-hao MeiAbstract:A number of experiments are underway to detect vacuum birefringence and dichroism — PVLAS, Q & A, and BMV. Recently, PVLAS experiment has observed optical rotation in vacuum by a magnetic field (vacuum dichroism). Theoretical interpretations of this result include a possible pseudoscalar–photon interaction and the existence of millicharged fermions. Here, we report the progress and first results of Q & A (QED [Quantum Electrodynamics] and Axion) experiment proposed and started in 1994. We use a 3.5-m high-finesse (around 30,000) Fabry–Perot prototype detector extendable to 7-m with the cavity mirrors suspended using X-pendulum-double pendulums. To polarize the vacuum, we use a 2.3-T dipole permanent magnet rotated at 5–10 rev/s, with 27-mm-diameter clear borehole and 0.6-m field length. Our ellipsometer/polarization-rotation-detection-system is formed by a pair of Glan–Taylor type polarizing prisms with extinction ratio lower than 10-8 together with a polarization modulating Faraday Cell with/without a quarter wave plate. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass with 18,700 passes through a 2.3 T 0.6 m long magnet for vacuum dichroism measurement. We present our experimental limit on pseudo-scalar-photon interaction and millicharged fermions.
Samina Masood - One of the best experts on this subject based on the ideXlab platform.
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QED Plasma at Extremely High Temperature and Density
arXiv: High Energy Physics - Phenomenology, 2020Co-Authors: Samina MasoodAbstract:We use the renormalization scheme of QED (Quantum Electrodynamics) in real-time formalism to calculate the effective parameters of the theory, indicating the existence of relativistic QED plasma at extremely high temperatures and extremely high densities. High-density plasma is found inside the stellar cores and high temperature QED plasma could only exist, right after the neutrino decoupling temperature in the early universe, before the nucleosynthesis is complete. Radiation couples with the medium through the vacuum polarization in a hot and dense medium. Calculating the vacuum polarization tensor in a medium, the effect of radiation on matter is investigated in such a medium. We explicitly compute the parameters of QED plasma such as plasma frequency, Debye shielding length and the propagation frequency in terms of temperature and density of the superhot and superdense medium, respectively. This study helps to understand short term existence of QED plasma in the superhot and superdense systems.
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QED Plasma at Finite Temperature up to Two Loops
arXiv: High Energy Physics - Phenomenology, 2018Co-Authors: Samina MasoodAbstract:We study the vacuum polarization tensor of QED (Quantum Electrodynamics) at high temperatures up to the two loop levels and its effect on the electromagnetic properties of a medium. One loop corrections to QED coupling vanish at low temperatures (T$\leq 10^{10}K$), but they play an important role at high temperature ( T$\geq 10^{10}$ K) to study the behavior of QED medium at these temperatures. At low temperatures ( $T \leq m_e$)higher order loops give a tiny correction due to the coupling of radiation with matter and an overlap of hot photon loop with cold fermion loop contributes to this effect. These higher loop contributions does not affect the convergence of perturbative series, and renormalizability of QED is guaranteed at temperatures around neutrino decoupling. We use the renormalization scheme of QED at finite temperature in real-time formalism to study the dynamically generated mass of photon indicating the plasmon production in such a medium. Temperature dependence of this QED plasma parameters is discussed. We explicitly show that this behavior of a thermal medium exists upto temperatures of a few MeV only. We compare the first order and second order effects upto the 4MeV temperature and demonstrate that the higher order contributions are smaller than the lower order contributions proving the renormalizability of the theory. The lowest order contributions are sufficiently smaller than the original value as well.
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Relativistic QED Plasma at Extremely High Temperature
arXiv: High Energy Astrophysical Phenomena, 2016Co-Authors: Samina MasoodAbstract:Renormalization scheme of QED (Quantum Electrodynamics) at high temperatures is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED play role of effective parameters of the theory and can be used to determine the collective behavior of the medium. We explicitly show that the dielectric constant, magnetic reluctivity, Debye length and the plasma frequency depend on temperature in the early universe. Propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma are computed at extremely high temperatures in the early universe. We also found the favorable conditions for the relativistic plasma from this calculations.
Kazuhide Ichikawa - One of the best experts on this subject based on the ideXlab platform.
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Computational Method for the Retarded Potential in the Real-Time Simulation of Quantum Electrodynamics
International Journal of Quantum Chemistry, 2016Co-Authors: Masahiro Fukuda, Kento Naito, Kazuhide Ichikawa, Akitomo TachibanaAbstract:We discuss the method to compute the integrals which appear in the retarded potential term for a real-time simulation based on QED (Quantum Electrodynamics). We show that the oscillatory integrals over the infinite interval involved in them can be efficiently performed by the method developed by Ooura and Mori based on the double exponential (DE) formula.
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Study of Simulation Method of Time Evolution in Rigged QED
International Journal of Quantum Chemistry, 2012Co-Authors: Kazuhide Ichikawa, Masahiro Fukuda, Akitomo TachibanaAbstract:We discuss how we formulate time evolution of physical quantities in the framework of the Rigged QED (Quantum Electrodynamics). The Rigged QED is a theory which has been proposed to treat dynamics of electrons, photons and atomic nuclei in atomic and molecular systems in a Quantum field theoretic way. To solve the dynamics in the Rigged QED, we need different techniques from those developed for the conventional QED. As a first step toward this issue, we propose a procedure to expand the Dirac field operator, which represents electrons, by the electron annihilation/creation operators and solutions of the Dirac equation for electrons in nuclear potential. Similarly, the Schrodinger field operators, which represent atomic nuclei, are expanded by nucleus annihilation/creation operators. Then we derive time evolution equations for these annihilation and creation operators and discuss how time evolution of the operators for physical quantities can be calculated. In the end, we propose a method to approximate the evolution equations of the operators by the evolution equations for the density matrices of electrons and atomic nuclei. Under this approximation, we carry out numerical simulation of the time evolution of electron charge density of a hydrogen atom.
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a theoretical study on a reaction of iron iii hydroxide with boron trichloride by ab initio calculation
Journal of Molecular Structure-theochem, 2009Co-Authors: Kazuhide Ichikawa, Toshiyuki Myoraku, Akinori Fukushima, Yoshio Ishihara, Ryuichiro Isaki, Toshio Takeguchi, Akitomo TachibanaAbstract:Abstract We investigate a reaction of boron trichloride ( BCl 3 ) with iron(III) hydroxide ( Fe ( OH ) 3 ) by ab initio Quantum chemical calculation as a simple model for a reaction of iron impurities in BCl 3 gas. We also examine a reaction with water. We find that compounds such as Fe ( Cl ) ( OBCl 2 ) 2 ( OHBCl 2 ) and Fe ( Cl ) 2 ( OBCl 2 ) ( OHBCl 2 ) are formed while producing HCl and reaction paths to them are revealed. We also analyze the stabilization mechanism of these paths using newly-developed interaction energy density derived from electronic stress tensor in the framework of the Regional DFT (Density Functional Theory) and Rigged QED (Quantum Electrodynamics).
