We discuss gravitational waves in an electroweakly interacting vector dark matter model. In the model, the electroweak gauge symmetry is extended to SU(2)0 × SU(2)1 × SU(2)2 × U(1)Y and spontaneously broken into SU(2)L × U(1)Y at TeV scale. The model has an exchange symmetry between SU(2)0 and SU(2)2. This symmetry stabilizes some massive vector bosons associated with the spontaneous symmetry breaking described above, and an electrically neutral one is a dark matter candidate. In the previous study, it was found that the gauge couplings of SU(2)0 and SU(2)1 are relatively large to explain the measured value of the dark matter energy density via the freeze-out mechanism. With the large gauge couplings, the gauge bosons potentially have a sizable effect on the scalar potential. In this paper, we focus on the phase transition of SU(2)0 × SU(2)1 × SU(2)2 → SU(2)L. We calculate the effective potential at finite temperature and find that the phase transition is first-order and strong in a wide range of the parameter space. The strong first-order phase transition generates gravitational waves. We calculate the gravitational wave spectrum and find that it is possible to detect the gravitational waves predicted in the model by future space-based gravitational wave interferometers. We explore the regions of the parameter space probed by the gravitational wave detection. We find that the gravitational wave detection can probe the region where the mass of h′, a CP-even scalar in the model, is a few TeV.
{"title":"Gravitational waves from first-order phase transition in an electroweakly interacting vector dark matter model","authors":"Tomohiro Abe, Katsuya Hashino","doi":"10.1093/ptep/ptae087","DOIUrl":"https://doi.org/10.1093/ptep/ptae087","url":null,"abstract":"We discuss gravitational waves in an electroweakly interacting vector dark matter model. In the model, the electroweak gauge symmetry is extended to SU(2)0 × SU(2)1 × SU(2)2 × U(1)Y and spontaneously broken into SU(2)L × U(1)Y at TeV scale. The model has an exchange symmetry between SU(2)0 and SU(2)2. This symmetry stabilizes some massive vector bosons associated with the spontaneous symmetry breaking described above, and an electrically neutral one is a dark matter candidate. In the previous study, it was found that the gauge couplings of SU(2)0 and SU(2)1 are relatively large to explain the measured value of the dark matter energy density via the freeze-out mechanism. With the large gauge couplings, the gauge bosons potentially have a sizable effect on the scalar potential. In this paper, we focus on the phase transition of SU(2)0 × SU(2)1 × SU(2)2 → SU(2)L. We calculate the effective potential at finite temperature and find that the phase transition is first-order and strong in a wide range of the parameter space. The strong first-order phase transition generates gravitational waves. We calculate the gravitational wave spectrum and find that it is possible to detect the gravitational waves predicted in the model by future space-based gravitational wave interferometers. We explore the regions of the parameter space probed by the gravitational wave detection. We find that the gravitational wave detection can probe the region where the mass of h′, a CP-even scalar in the model, is a few TeV.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Saadi Ishaq, Sajawal Zafar, Abdur Rehman, Ishtiaq Ahmed
Motivated by the study of heavy-light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for rather a complicated process W+ → B+ℓ+ℓ− in the limit of non-zero invariant squared-mass of dilepton, q2, at the lowest order in 1/mb up to $mathcal {O}(alpha _s)$. The purpose of the current study is to extend the HQET factorization formula for the W+ → B+ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading order (NLO) corrections in αs. We explicitly show the amplitude of the W+ → B+ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the non-perturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W+ → B+ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W+ → B+ℓ+ℓ− by employing an exponential model for the LCDAs for B+ meson. Our findings reveal that the branching ratio for W+ → B+ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high luminosity LHC experiments may serve to further constraints the value of λB.
{"title":"Semi-leptonic W decay to B meson with lepton pairs in HQET factorization upto O","authors":"Saadi Ishaq, Sajawal Zafar, Abdur Rehman, Ishtiaq Ahmed","doi":"10.1093/ptep/ptae080","DOIUrl":"https://doi.org/10.1093/ptep/ptae080","url":null,"abstract":"Motivated by the study of heavy-light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for rather a complicated process W+ → B+ℓ+ℓ− in the limit of non-zero invariant squared-mass of dilepton, q2, at the lowest order in 1/mb up to $mathcal {O}(alpha _s)$. The purpose of the current study is to extend the HQET factorization formula for the W+ → B+ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading order (NLO) corrections in αs. We explicitly show the amplitude of the W+ → B+ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the non-perturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W+ → B+ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W+ → B+ℓ+ℓ− by employing an exponential model for the LCDAs for B+ meson. Our findings reveal that the branching ratio for W+ → B+ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high luminosity LHC experiments may serve to further constraints the value of λB.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the collective mode of a self-gravitating Bose-Einstein condensate (BEC) described by the Gross-Pitaevskii-Poisson (GPP) equations. The self-gravitating BEC has garnered considerable attention in cosmology and astrophysics, being proposed as a plausible candidate for dark matter. Our inquiry delves into the breathing and anisotropic collective modes by numerically solving the GPP equations and using the variational method. The breathing mode demonstrates a reduction in period with increasing total mass due to the density dependence of the self-gravitating BEC, attributed to the density-dependent nature of self-gravitating BECs, aligning quantitatively with our analytical findings. Additionally, we investigate an anisotropic collective mode in which the quadrupole mode intertwines with the breathing mode. The period of the quadrupole mode exhibits similar total mass dependence to that of the breathing mode. The characteristics of these periods differ from those of a conventional BEC confined by an external potential. Despite the differences in density dependence, the ratio of their periods equals that of the BEC confined by an isotropic harmonic potential. Furthermore, an extension of the variational method to a spheroidal configuration enables the isolation of solely the quadrupole mode from the anisotropic collective mode.
{"title":"Collective excitations of self-gravitating bose-einstein condensates: Breathing mode and appearance of anisotropy under self-gravity","authors":"Kenta Asakawa, Hideki Ishihara, Makoto Tsubota","doi":"10.1093/ptep/ptae078","DOIUrl":"https://doi.org/10.1093/ptep/ptae078","url":null,"abstract":"We investigate the collective mode of a self-gravitating Bose-Einstein condensate (BEC) described by the Gross-Pitaevskii-Poisson (GPP) equations. The self-gravitating BEC has garnered considerable attention in cosmology and astrophysics, being proposed as a plausible candidate for dark matter. Our inquiry delves into the breathing and anisotropic collective modes by numerically solving the GPP equations and using the variational method. The breathing mode demonstrates a reduction in period with increasing total mass due to the density dependence of the self-gravitating BEC, attributed to the density-dependent nature of self-gravitating BECs, aligning quantitatively with our analytical findings. Additionally, we investigate an anisotropic collective mode in which the quadrupole mode intertwines with the breathing mode. The period of the quadrupole mode exhibits similar total mass dependence to that of the breathing mode. The characteristics of these periods differ from those of a conventional BEC confined by an external potential. Despite the differences in density dependence, the ratio of their periods equals that of the BEC confined by an isotropic harmonic potential. Furthermore, an extension of the variational method to a spheroidal configuration enables the isolation of solely the quadrupole mode from the anisotropic collective mode.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, lattice formulations of Abelian chiral gauge theory in two dimensions have been devised on the basis of the Abelian bosonization. A salient feature of these two-dimensional lattice formulations is that the gauge invariance is exactly preserved for anomaly-free theories and thus is completely free from the question of the gauge mode decoupling. In the present paper, we propose a yet another lattice formulation sharing this desired property. A particularly unique point in our formulation is that the vertex operator of the dual scalar field, which carries the vector charge of the fermion and the “magnetic charge” in the bosonization, is represented by a “hole” excised from the lattice; this is the excision method formulated recently by Abe et al. in a somewhat different context.
{"title":"Yet another lattice formulation of 2D U(1) chiral gauge theory via bosonization","authors":"Okuto Morikawa, Soma Onoda, Hiroshi Suzuki","doi":"10.1093/ptep/ptae075","DOIUrl":"https://doi.org/10.1093/ptep/ptae075","url":null,"abstract":"\u0000 Recently, lattice formulations of Abelian chiral gauge theory in two dimensions have been devised on the basis of the Abelian bosonization. A salient feature of these two-dimensional lattice formulations is that the gauge invariance is exactly preserved for anomaly-free theories and thus is completely free from the question of the gauge mode decoupling. In the present paper, we propose a yet another lattice formulation sharing this desired property. A particularly unique point in our formulation is that the vertex operator of the dual scalar field, which carries the vector charge of the fermion and the “magnetic charge” in the bosonization, is represented by a “hole” excised from the lattice; this is the excision method formulated recently by Abe et al. in a somewhat different context.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140968238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the effects of residual tensor force (TF) and pairing force on the Gamow-Teller (GT) transitions in four magic nuclei, 48Ca, 90Zr, 132Sn and 208Pb. The TF is taken into account by using the Brückner G-matrix theory with the charge-dependent (CD) Bonn potential as the residual interaction of charge-exchange quasiparticle random phase approximation (QRPA). We found that particle-particle (p − p) tensor interaction does not affect the GT transitions because of the closed shell nature in the nuclei, but repulsive particle-hole (p − h) residual interaction for the p − h configuration of spin-orbit partners dominates the high-lying giant GT states for all of the nuclei. It is also shown that appreciable GT strengths are shifted to lower energy region by the attractive p − h TF for the same jπ = jν configuration, and produce the low-lying GT peak about 2.5 MeV in 48Ca. Simultaneously, in 90Zr and 132Sn, the low-energy GT strength appears as a lower energy shoulder near the main GT peak. On the other hand, the shift of the low-lying GT state is not seen clearly for 208Pb because of the strong spin-orbit splitting of high j orbits, which dominates the GT strength.
{"title":"Effects of Residual Tensor and Pairing Forces on the Gamow-Teller states in Magic Nuclei, 48Ca, 90Zr, 132Sn, and 208Pb","authors":"E. Ha, M. Cheoun, H. Sagawa","doi":"10.1093/ptep/ptae077","DOIUrl":"https://doi.org/10.1093/ptep/ptae077","url":null,"abstract":"\u0000 We investigate the effects of residual tensor force (TF) and pairing force on the Gamow-Teller (GT) transitions in four magic nuclei, 48Ca, 90Zr, 132Sn and 208Pb. The TF is taken into account by using the Brückner G-matrix theory with the charge-dependent (CD) Bonn potential as the residual interaction of charge-exchange quasiparticle random phase approximation (QRPA). We found that particle-particle (p − p) tensor interaction does not affect the GT transitions because of the closed shell nature in the nuclei, but repulsive particle-hole (p − h) residual interaction for the p − h configuration of spin-orbit partners dominates the high-lying giant GT states for all of the nuclei. It is also shown that appreciable GT strengths are shifted to lower energy region by the attractive p − h TF for the same jπ = jν configuration, and produce the low-lying GT peak about 2.5 MeV in 48Ca. Simultaneously, in 90Zr and 132Sn, the low-energy GT strength appears as a lower energy shoulder near the main GT peak. On the other hand, the shift of the low-lying GT state is not seen clearly for 208Pb because of the strong spin-orbit splitting of high j orbits, which dominates the GT strength.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140966613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pairing correlations play an important role in a variety of nuclear phenomena. However, a quantitative understanding of proton–neutron (pn) pairing, especially isoscalar pn pairing (S = 1, T = 0) remains elusive. To clarify the property of pn pairing, we investigate the roles of pn pairing in the M1 transition of N = Z odd–odd nuclei. We develop a theoretical model based on the generator coordinate method (GCM) in which the isoscalar and isovector pn-pair amplitudes are used as the generator coordinates. Using the particle and the angular-momentum projections, the pn-pair GCM well reproduces the M1 transition of odd–odd nuclei for the exactly solvable SO(8) model. We apply the method to N = Z odd–odd nuclei and find that the experimental values of B(M1) are well reproduced. We also study the sensitivity of B(M1) to the strength of the isoscalar pairing interaction.
配对相关性在各种核现象中发挥着重要作用。然而，对质子-中子（pn）配对，尤其是等标pn配对（S = 1，T = 0）的定量理解仍然是个未知数。为了澄清 pn 配对的特性，我们研究了 pn 配对在 N = Z 奇多核的 M1 转变中的作用。我们建立了一个基于生成器坐标法（GCM）的理论模型，其中使用等视角和等矢量 pn 对振幅作为生成器坐标。利用粒子和角动量投影，pn 对 GCM 很好地再现了可精确求解的 SO(8) 模型中奇-偶核的 M1 转变。我们将该方法应用于 N = Z 奇-多原子核，发现 B(M1)的实验值得到了很好的再现。我们还研究了 B(M1)对等离子配对相互作用强度的敏感性。
{"title":"Generator coordinate method with proton–neutron pairing fluctuations and magnetic properties of N = Z odd–odd nuclei","authors":"K Uzawa, N Hinohara, T Nakatsukasa","doi":"10.1093/ptep/ptae072","DOIUrl":"https://doi.org/10.1093/ptep/ptae072","url":null,"abstract":"Pairing correlations play an important role in a variety of nuclear phenomena. However, a quantitative understanding of proton–neutron (pn) pairing, especially isoscalar pn pairing (S = 1, T = 0) remains elusive. To clarify the property of pn pairing, we investigate the roles of pn pairing in the M1 transition of N = Z odd–odd nuclei. We develop a theoretical model based on the generator coordinate method (GCM) in which the isoscalar and isovector pn-pair amplitudes are used as the generator coordinates. Using the particle and the angular-momentum projections, the pn-pair GCM well reproduces the M1 transition of odd–odd nuclei for the exactly solvable SO(8) model. We apply the method to N = Z odd–odd nuclei and find that the experimental values of B(M1) are well reproduced. We also study the sensitivity of B(M1) to the strength of the isoscalar pairing interaction.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We fill some of existed gaps in the correspondence between Supersymmetric Quantum Mechanics and the Inverse Scattering Transform by extending the consideration to the case of paired stationary and non-stationary Hamiltonians. We formulate the corresponding to the case Goursat problem and explicitly construct the kernel of the non-local Inverse Scattering Transform, which solves it. As a result, we find the way of constructing non-hermitian Hamiltonians from the initially hermitian ones, that leads, in the case of real-valued spectra of both potentials, to pairing of ${cal CPT/PT}$-invariant Hamiltonians. The relevance of our proposal to Quantum Optics and optical waveguides technology, as well as to non-linear dynamics and Black Hole Physics is briefly discussed.
{"title":"Non-stationary SQM/IST correspondence and CPT/PT-invariant paired hamiltonians on the line","authors":"V P Berezovoj, A J Nurmagambetov","doi":"10.1093/ptep/ptae074","DOIUrl":"https://doi.org/10.1093/ptep/ptae074","url":null,"abstract":"We fill some of existed gaps in the correspondence between Supersymmetric Quantum Mechanics and the Inverse Scattering Transform by extending the consideration to the case of paired stationary and non-stationary Hamiltonians. We formulate the corresponding to the case Goursat problem and explicitly construct the kernel of the non-local Inverse Scattering Transform, which solves it. As a result, we find the way of constructing non-hermitian Hamiltonians from the initially hermitian ones, that leads, in the case of real-valued spectra of both potentials, to pairing of ${cal CPT/PT}$-invariant Hamiltonians. The relevance of our proposal to Quantum Optics and optical waveguides technology, as well as to non-linear dynamics and Black Hole Physics is briefly discussed.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Krylov complexity is considered to provide a measure of the growth of operators evolving under Hamiltonian dynamics. The main strategy is the analysis of the structure of Krylov subspace $mathcal {K}_M(mathcal {H},eta )$ spanned by the multiple applications of the Liouville operator $mathcal {L}$ defined by the commutator in terms of a Hamiltonian $mathcal {H}$, $mathcal {L}:=[mathcal {H},cdot ]$ acting on an operator η, $mathcal {K}_M(mathcal {H},eta )=text{span}lbrace eta ,mathcal {L}eta ,ldots ,mathcal {L}^{M-1}eta rbrace$. For a given inner product ( ·, ·) of the operators, the orthonormal basis $lbrace mathcal {O}_nrbrace$ is constructed from $mathcal {O}_0=eta /sqrt{(eta ,eta )}$ by Lanczos algorithm. The moments $mu _m=(mathcal {O}_0,mathcal {L}^mmathcal {O}_0)$ are closely related to the important data {bn} called Lanczos coefficients. I present the exact and explicit expressions of the moments {μm} for 16 quantum mechanical systems which are exactly solvable both in the Schrödinger and Heisenberg pictures. The operator η is the variable of the eigenpolynomials. Among them six systems show a clear sign of ‘non-complexity’ as vanishing higher Lanczos coefficients bm = 0, m ≥ 3.
{"title":"Towards verifications of Krylov complexity","authors":"Ryu Sasaki","doi":"10.1093/ptep/ptae073","DOIUrl":"https://doi.org/10.1093/ptep/ptae073","url":null,"abstract":"Krylov complexity is considered to provide a measure of the growth of operators evolving under Hamiltonian dynamics. The main strategy is the analysis of the structure of Krylov subspace $mathcal {K}_M(mathcal {H},eta )$ spanned by the multiple applications of the Liouville operator $mathcal {L}$ defined by the commutator in terms of a Hamiltonian $mathcal {H}$, $mathcal {L}:=[mathcal {H},cdot ]$ acting on an operator η, $mathcal {K}_M(mathcal {H},eta )=text{span}lbrace eta ,mathcal {L}eta ,ldots ,mathcal {L}^{M-1}eta rbrace$. For a given inner product ( ·, ·) of the operators, the orthonormal basis $lbrace mathcal {O}_nrbrace$ is constructed from $mathcal {O}_0=eta /sqrt{(eta ,eta )}$ by Lanczos algorithm. The moments $mu _m=(mathcal {O}_0,mathcal {L}^mmathcal {O}_0)$ are closely related to the important data {bn} called Lanczos coefficients. I present the exact and explicit expressions of the moments {μm} for 16 quantum mechanical systems which are exactly solvable both in the Schrödinger and Heisenberg pictures. The operator η is the variable of the eigenpolynomials. Among them six systems show a clear sign of ‘non-complexity’ as vanishing higher Lanczos coefficients bm = 0, m ≥ 3.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140938204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pulsar wind nebulae (PWNe) are clouds of the magnetized relativistic electron/positron plasma supplied from the central pulsar. However, the number of radio-emitting particles inside a PWN is larger than the expectation from the study of pulsar magnetospheres and then their origin is still unclear. A stochastic acceleration of externally injected particles by a turbulence inside the PWN is proposed by our previous studies. In this paper, the previous stochastic acceleration model of the PWN broadband spectra is improved by taking into account the time evolution of the turbulent energy and then the total energy balance inside a PWN is maintained. The turbulent energy supplied from the central pulsar is wasted by the backreaction from the stochastic particle acceleration and the adiabatic cooling according the PWN expansion. The model is applied to the Crab Nebula and reproduce the current broadband emission spectrum, especially the flat radio spectrum although time evolution of the turbulent energy (diffusion coefficient) is a bit complicated compared with our previous studies, where we assumed an exponential behavior of the diffusion coefficient.
{"title":"A self-regulated stochastic acceleration model of pulsar wind nebulae","authors":"Shuta J Tanaka, Wataru Ishizaki","doi":"10.1093/ptep/ptae069","DOIUrl":"https://doi.org/10.1093/ptep/ptae069","url":null,"abstract":"Pulsar wind nebulae (PWNe) are clouds of the magnetized relativistic electron/positron plasma supplied from the central pulsar. However, the number of radio-emitting particles inside a PWN is larger than the expectation from the study of pulsar magnetospheres and then their origin is still unclear. A stochastic acceleration of externally injected particles by a turbulence inside the PWN is proposed by our previous studies. In this paper, the previous stochastic acceleration model of the PWN broadband spectra is improved by taking into account the time evolution of the turbulent energy and then the total energy balance inside a PWN is maintained. The turbulent energy supplied from the central pulsar is wasted by the backreaction from the stochastic particle acceleration and the adiabatic cooling according the PWN expansion. The model is applied to the Crab Nebula and reproduce the current broadband emission spectrum, especially the flat radio spectrum although time evolution of the turbulent energy (diffusion coefficient) is a bit complicated compared with our previous studies, where we assumed an exponential behavior of the diffusion coefficient.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140938124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We use the anti-de Sitter/conformal field theory (AdS/CFT) correspondence to find the least bounce action in an AdS false vacuum state, i.e., the most probable decay process of the metastable AdS vacuum within the Euclidean formalism by Callan and Coleman. It was shown that the O(4) symmetric bounce solution leads to the action minimum in the absence of gravity, but it is non-trivial in the presence of gravity. The AdS/CFT duality is used to evade the difficulties particular to a metastable gravitational system. To this end, we show that the Fubini bounce solution in CFT, corresponding to the Coleman de Luccia (CdL) bounce in AdS, gives the least action among all finite bounce solutions in a conformal scalar field theory. Thus, we prove that the CdL action is the least action among all possible large and thin-wall configurations under certain conditions.
{"title":"Is the coleman de luccia action minimum?: AdS/CFT approach","authors":"Naritaka Oshita, Yutaro Shoji, Masahide Yamaguchi","doi":"10.1093/ptep/ptae068","DOIUrl":"https://doi.org/10.1093/ptep/ptae068","url":null,"abstract":"We use the anti-de Sitter/conformal field theory (AdS/CFT) correspondence to find the least bounce action in an AdS false vacuum state, i.e., the most probable decay process of the metastable AdS vacuum within the Euclidean formalism by Callan and Coleman. It was shown that the O(4) symmetric bounce solution leads to the action minimum in the absence of gravity, but it is non-trivial in the presence of gravity. The AdS/CFT duality is used to evade the difficulties particular to a metastable gravitational system. To this end, we show that the Fubini bounce solution in CFT, corresponding to the Coleman de Luccia (CdL) bounce in AdS, gives the least action among all finite bounce solutions in a conformal scalar field theory. Thus, we prove that the CdL action is the least action among all possible large and thin-wall configurations under certain conditions.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140938075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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