Endo Shimpei
| Department of Engineering Science | Associate Professor |
| Cluster III (Fundamental Science and Engineering) | Associate Professor |
| Institute for Advanced Science | Associate Professor |
Researcher Information
Research Keyword
Field Of Study
Career
- Oct. 2023 - Present
The University of Electro-Communications, Graduate School of Informatics and Engineering, Associate Professor, Japan - Sep. 2021 - Sep. 2023
Tohoku University, Graduate School of Science Department of Physics, Assistant Professor, Japan - Jul. 2021 - Sep. 2023
Tohoku University Prominent Research Fellow - Apr. 2018 - Aug. 2021
Tohoku University, Frontier Reserach Institute for Interdisciplinary Science (FRIS), Assistant Professor - Jan. 2018 - Mar. 2018
Australian Research Council (ARC), DECRA Fellow - May 2016 - Mar. 2018
Monash University, School of Physics & Astronomy, Reserach Fellow - Apr. 2014 - Mar. 2016
Ecole Normale Superieure, Laboratoire-Kastler Brossel, JSPS Postdoctoral Fellowships for Research Abroad - Apr. 2011 - Mar. 2014
JSPS, Research Fellow (DC1)
Educational Background
Research Activity Information
Award
- Oct. 2022
Tohoku Univ.
冷却原子気体における量子少数多体問題の理論研究
Senshu-kai Prize, 遠藤晋平 - Apr. 2020
IOP Publishing
Journal of Physics B: Atomic, Molecular and Optical Physics (2019)
Outstanding Reviewer, Shimpei Endo - Mar. 2020
Japanese Physical Society
Young Scientist Award of the Physical Society of Japan, Shimpei Endo - Jun. 2013
第10回AMO討論会
ポスター発表賞, 遠藤晋平 - Mar. 2012
Japanese Physical Society
Japanese Physical Society Student Presentation Prize (Divisinon 1), Shimpei Endo - Mar. 2011
Faculty of Science, University of Tokyo
Research Awards for Master Students, Shimpei Endo - Sep. 2009
スーパークリーン特定 若手秋の学校
ポスター賞, 遠藤晋平
Paper
- Three-body forces and Efimov physics in nuclei and atoms
Shimpei Endo; Evgeny Epelbaum; Pascal Naidon; Yusuke Nishida; Kimiko Sekiguchi; Yoshiro Takahashi
Lead, The European Physical Journal A, 61, 9, 22 Jan. 2025, Peer-reviwed
Scientific journal, English - Complex-valued in-medium potential between heavy impurities in ultracold atoms
Yukinao Akamatsu; Shimpei Endo; Keisuke Fujii; Masaru Hongo
Physical Review A, American Physical Society (APS), 110, 3, 033304, 03 Sep. 2024, Peer-reviwed
Scientific journal, English - Universality of Efimov states in highly mass-imbalanced cold-atom mixtures with van der Waals and dipole interactions
Kazuki Oi; Pascal Naidon; Shimpei Endo
Last, Physical Review A, American Physical Society (APS), 110, 3, 033305, 03 Sep. 2024, Peer-reviwed, We study three-body systems in a mass-imbalanced, two-component, cold-atom mixture, and we investigate the three-body parameter of their Efimov states for both bosonic and fermionic systems, with a major focus on the Er-Er-Li Efimov states. For a system interacting solely via van der Waals interactions, the van der Waals universality of the three-body parameter is analytically derived using the quantum defect theory. With the addition of a perturbative dipole interaction between the heavy atoms, the three-body parameters of the bosonic and fermionic Efimov states are found to behave differently. When the dipole interaction is as strong as the van der Waals interaction, corresponding to realistic Er-Er-Li Efimov states, we show that the van der Waals universality persists once the effects of the nonperturbative dipole interaction are into the s-wave and p-wave scattering parameters between the heavy atoms. For a dipole interaction much stronger than the van der Waals interaction, we find that the universality of the Efimov states can be alternatively characterized by a quasi-one-dimensional scattering parameter due to a strong anisotropic deformation of the Efimov wave functions. Our work thus clarifies the interplay of isotropic and anisotropic forces in the universality of the Efimov states. Based on the renormalized van der Waals universality, the three-body parameter is estimated for specific isotopes of Er-Li cold-atom mixtures.
Published by the American Physical Society 2024
Scientific journal, English - Topological phases and edge modes of an uneven ladder
Wen-Chuang Shang; Yi-Ning Han; Shimpei Endo; Chao Gao
Chinese Physics B, IOP Publishing, 33, 8, 080202-080202, 01 Jul. 2024, Abstract
We investigate the topological properties of a two-chain quantum ladder with uneven legs, i.e., the two chains differ in their periods by a factor of 2. Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps. It also provides opportunities to explore fundamental concepts concerning band topology and edge modes, including the difference of intracellular and intercellular Zak phases, and the role of the inversion symmetry (IS). We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation. We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap, while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum. Furthermore, by projecting to the two sublattices, we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum. In this way, the topological phases can be efficiently extracted through winding numbers. We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.
Scientific journal, English - Quatrièmes coefficients d’amas et du viriel d’un gaz unitaire de fermions pour un rapport de masse quelconque
Shimpei Endo; Yvan Castin
Lead, Comptes Rendus Physique, Cellule MathDoc/CEDRAM, 23, G1, 41-110, 12 Aug. 2022, Peer-reviwed
Scientific journal, English - Erratum: Physical origin of the universal three-body parameter in atomic Efimov physics [Phys. Rev. A 90, 022106 (2014)]
Pascal Naidon; Shimpei Endo; Masahito Ueda
Physical Review A, American Physical Society (APS), 104, 5, 059903, 10 Nov. 2021
Scientific journal, English - On deformability of atoms - Comparative study between atoms and atomic nuclei
Tomoya Naito; Shimpei Endo; Kouichi Hagino; Yusuke Tanimura
Journal of Physics B: Atomic, Molecular and Optical Physics, IOP Publishing, 54, 16, 165201, 21 Sep. 2021, Peer-reviwed, Atomic nuclei can be spontaneously deformed into non-spherical shapes as many-nucleon systems. We discuss to what extent a similar deformation takes place in many-electron systems. To this end, we employ several many-body methods, such as the unrestricted Hartree-Fock method, post-Hartree-Fock methods, and the density functional theory, to compute the electron density distribution in atoms. We show that the electron density distribution of open-shell atoms is deformed due solely to the single-particle valence orbitals, while the core part remains spherical. This is in contrast to atomic nuclei, which can be deformed collectively. We qualitatively discuss the origin for this apparent difference between atoms and nuclei by estimating the energy change due to deformation. We find that nature of the interaction plays an essential role for the collective deformation.
Scientific journal, English - Equivalence of dissipative and dissipationless dynamics of interacting quantum systems with its application to the unitary Fermi gas
Masaaki Tokieda; Shimpei Endo
Lead, Frontiers in Physics - Rising Star in Asia, 9, 730761, 17 Sep. 2021, Peer-reviwed, Invited
Scientific journal, English - Virial expansion coefficients in the unitary Fermi gas
Shimpei Endo
Lead, SciPost Phys. Proc., 3, 049, 27 Feb. 2020, Peer-reviwed
International conference proceedings, English - Eigenvalues of Two-State Quantum Walks Induced by the Hadamard Walk
Shimpei Endo; Takako Endo; Takashi Komatsu; Norio Konno
Lead, Entropy, MDPI AG, 22, 1, 127-127, 20 Jan. 2020, Peer-reviwed, Existence of the eigenvalues of the discrete-time quantum walks is deeply related to localization of the walks. We revealed, for the first time, the distributions of the eigenvalues given by the splitted generating function method (the SGF method) of the space-inhomogeneous quantum walks in one dimension we had treated in our previous studies. Especially, we clarified the characteristic parameter dependence for the distributions of the eigenvalues with the aid of numerical simulation.
Scientific journal, English - Universality of quantum few-body systems and Efimov physics
Shimpei Endo
Lead, Genshikaku Kenkyu, 64, 1, 90-105, Sep. 2019, Peer-reviwed
Scientific journal, Japanese - Universality of an Impurity in a Bose-Einstein Condensate
Shuhei M. Yoshida; Shimpei Endo; Jesper Levinsen; Meera M. Parish
Physical Review X, American Physical Society, 8, 1, 011024-011024, 13 Feb. 2018, Peer-reviwed, We consider the ground-state properties of an impurity particle ("polaron") resonantly interacting with a Bose-Einstein condensate (BEC). Focusing on the equal-mass system, we use a variational wave function for the polaron that goes beyond previous work and includes up to three Bogoliubov excitations of the BEC, thus allowing us to capture both Efimov trimers and associated tetramers. We find that the length scale associated with Efimov trimers (i.e., the three-body parameter) can strongly affect the polaron's behavior, even at densities where there are no well-defined Efimov states. However, by comparing our results with recent quantum Monte Carlo calculations, we argue that the polaron energy is a universal function of the Efimov three-body parameter for sufficiently low boson densities. We further support this conclusion by showing that the energies of the deepest bound Efimov trimers and tetramers at unitarity are universally related to one another, regardless of the microscopic model. On the other hand, we find that the quasiparticle residue and effective mass sensitively depend on the coherence length ξ of the BEC, with the residue tending to zero as ξ diverges, in a manner akin to the orthogonality catastrophe.
Scientific journal, English - Efimov physics: a review
Pascal Naidon; Shimpei Endo
Lead, REPORTS ON PROGRESS IN PHYSICS, IOP PUBLISHING LTD, 80, 5, 056001, May 2017, Peer-reviwed, This article reviews theoretical and experimental advances in Efimov physics, an array of quantum few-body and many-body phenomena arising for particles interacting via short-range resonant interactions, that is based on the appearance of a scale-invariant three-body attraction theoretically discovered by Vitaly Efimov in 1970. This three-body effect was originally proposed to explain the binding of nuclei such as the triton and the Hoyle state of carbon-12, and later considered as a simple explanation for the existence of some halo nuclei. It was subsequently evidenced in trapped ultra-cold atomic clouds and in diffracted molecular beams of gaseous helium. These experiments revealed that the previously undetermined three-body parameter introduced in the Efimov theory to stabilise the three-body attraction typically scales with the range of atomic interactions. The few-and many-body consequences of the Efimov attraction have been since investigated theoretically, and are expected to be observed in a broader spectrum of physical systems.
Scientific journal, English - Universality of the unitary Fermi gas: a few-body perspective
Jesper Levinsen; Pietro Massignan; Shimpei Endo; Meera M. Parish
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, IOP PUBLISHING LTD, 50, 7, 072001, Apr. 2017, Peer-reviwed, We revisit the properties of the two-component Fermi gas with short-range interactions in three dimensions, in the limit where the s-wave scattering length diverges. Such a unitary Fermi gas possesses universal thermodynamic and dynamical observables that are independent of any interaction length scale. Focusing on trapped systems of N fermions, where N <= 10, we investigate how well we can determine the zero-temperature behavior of the many-body system from published few-body data on the ground-state energy and the contact. For the unpolarized case, we find that the Bertsch parameters extracted from trapped few-body systems all lie within 15% of the established value. Furthermore, the few-body values for the contact are well within the range of values determined in the literature for the many-body system. In the limit of large spin polarization, we obtain a similar accuracy for the polaron energy, and we estimate the polaron's effective mass from the dependence of its energy on N. We also compute an upper bound for the squared wave-function overlap between the unitary Fermi system and the noninteracting ground state, both for the trapped and uniform cases. This allows us to prove that the trapped unpolarized ground state at unitarity has zero overlap with its non-interacting counterpart in the many-body limit N -> infinity.
Scientific journal, English - Unitary boson-boson and boson-fermion mixtures: third virial coefficient and three-body parameter on a narrow Feshbach resonance
Shimpei Endo; Yvan Castin
Lead, EUROPEAN PHYSICAL JOURNAL D, SPRINGER, 70, 11, 238, Nov. 2016, Peer-reviwed, We give exact integral expressions of the third cluster or virial coefficients of binary mixtures of ideal Bose or Fermi gases, with interspecies interactions of zero range and infinite s-wave scattering length. In general the result depends on three-body parameters Rt appearing in three-body contact conditions, because an Efimov effect is present or because the mixture is in a preefimovian regime with a mass ratio close to an Efimov-effect threshold. We give a new, exact integral expression of Rt for the microscopic narrow Feshbach resonance model. A divergence of Rt in the preefimovian regime at a scaling exponent s = 1/2 is predicted and physically discussed. The analytical results are applied to typical species used in cold atom experiments.
Scientific journal, English - The interaction-sensitive states of a trapped two-component ideal Fermi gas and application to the virial expansion of the unitary Fermi gas
Shimpei Endo; Yvan Castin
Lead, JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, IOP PUBLISHING LTD, 49, 26, 265301, Jul. 2016, Peer-reviwed, We consider a two-component ideal Fermi gas in an isotropic harmonic potential. Some eigenstates have a wavefunction that vanishes when two distinguishable fermions are at the same location, and would be unaffected by s-wave contact interactions between the two components. We determine the other, interaction-sensitive eigenstates, using a Faddeev ansatz. This problem is nontrivial, due to degeneracies and to the existence of unphysical Faddeev solutions. As an application we present a new conjecture for the fourth-order cluster or virial coefficient of the unitary Fermi gas, in good agreement with the numerical results of Blume and coworkers.
Scientific journal, English - Universal clusters as building blocks of stable quantum matter
Shimpei Endo; Antonio M. Garcia-Garcia; Pascal Naidon
Lead, PHYSICAL REVIEW A, AMER PHYSICAL SOC, 93, 5, 053611, May 2016, Peer-reviwed, We present an exploratory study that suggests that Efimov physics, a leading research theme in few-body quantum physics, can also induce stable many-body ground states whose building blocks are universal clusters. We identify a range of parameters in a mass-and-density-imbalanced two-species fermionic mixture for which the ground state is a gas of Efimov-related universal trimers. An explicit calculation of the trimer-trimer interaction reveals that the trimer phase is an SU(3) Fermi liquid stable against recombination losses. We propose to experimentally observe this phase in a fermionic Li-6-Cr-53 mixture.
Scientific journal, English - Weak limit theorem of a two-phase quantum walk with one defect
Shimpei Endo; Takako Endo; Norio Konno; Etsuo Segawa; Masato Takei
Lead, Interdisciplinary Information Sciences, Vol.22, 17-29 (2016), Graduate School of Information Sciences, Tohoku University, 22, 1, 17-29, Mar. 2016, Peer-reviwed, We attempt to analyze a one-dimensional space-inhomogeneous quantum walk (QW)
with one defect at the origin, which has two different quantum coins in
positive and negative parts. We call the QW "the two-phase QW", which we
treated concerning localization theorems [10]. The two-phase QW has been
expected to be a mathematical model of the topological insulator [16] which is
an intense issue both theoretically and experimentally [3,5,11]. In this paper,
we derive the weak limit theorem describing the ballistic spreading, and as a
result, we obtain the mathematical expression of the whole picture of the
asymptotic behavior. Our approach is based mainly on the generating function of
the weight of the passages. We emphasize that the time-averaged limit measure
is symmetric for the origin [10], however, the weak limit measure is
asymmetric, which implies that the weak limit theorem represents the asymmetry
of the probability distribution.
Scientific journal, English - Scattering of universal fermionic clusters in the resonating group method
Pascal Naidon; Shimpei Endo; Antonio M. Garcia-Garcia
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, IOP PUBLISHING LTD, 49, 3, 034002, Feb. 2016, Peer-reviwed, Mixtures of polarized fermions of two different masses can form weakly bound clusters, such as dimers and trimers, that are universally described by the scattering length between the heavy and light fermions. We use the resonating group method to investigate the low-energy scattering processes involving dimers or trimers. The method reproduces approximately the known particle-dimer and dimer-dimer scattering lengths. We use it to estimate the trimer-trimer scattering length, which is presently unknown, and find it to be positive.
Scientific journal, English - LIMIT THEOREMS OF A TWO-PHASE QUANTUM WALK WITH ONE DEFECT
Shimpei Endo; Takako Endo; Norio Konno; Etsuo Segawa; Masato Takei
Lead, QUANTUM INFORMATION & COMPUTATION, RINTON PRESS, INC, 15, 15-16, 1373-1396, Nov. 2015, Peer-reviwed, We treat a position dependent quantum walk (QW) on the line which we assign two different time-evolution operators to positive and negative parts respectively. We call the model "the two-phase QW" here, which has been expected to be a mathematical model of the topological insulator. We obtain the stationary and time-averaged limit measures related to localization for the two-phase QW with one defect. This is the first result on localization for the two-phase QW. The analytical methods are mainly based on the splitted generating function of the solution for the eigenvalue problem, and the generating function of the weight of the passages of the model. In this paper, we call the methods "the splitted generating function method" and "the generating function method", respectively. The explicit expression of the stationary measure is asymmetric for the origin, and depends on the initial state and the choice of the parameters of the model. On the other hand, the time-averaged limit measure has a starting point symmetry and localization effect heavily depends on the initial state and the parameters of the model. Regardless of the strong effect of the initial state and the parameters, the time-averaged limit measure also suggests that localization can be always observed for our two-phase QW. Furthermore, our results imply that there is an interesting relation between the stationary and time-averaged limit measures when the parameters of the model have specific periodicities, which suggests that there is a possibility that we can analyze localization of the two-phase QW with one defect from the stationary measure.
Scientific journal, English - Absence of a four-body Efimov effect in the 2+2 fermionic problem
Shimpei Endo; Yvan Castin
Lead, PHYSICAL REVIEW A, AMER PHYSICAL SOC, 92, 5, 053624, Nov. 2015, Peer-reviwed, In the free three-dimensional space, we consider a pair of identical up arrow fermions of some species or in some internal state and a pair of identical down arrow fermions of another species or in another state. There is a resonant s-wave interaction (that is, of zero range and infinite scattering length) between fermions in different pairs and no interaction within the same pair. We study whether this 2 + 2 fermionic system can exhibit (as the 3 + 1 fermionic system) a four-body Efimov effect in the absence of three-body Efimov effect, that is, the mass ratio a between up arrow and down arrow fermions and its inverse are both smaller than 13.6069 .... For this purpose, we investigate scale invariant zero-energy solutions of the four-body Schrodinger equation, that is, positively homogeneous functions of the coordinates of degree s - 7/2, where s is a generalized Efimov exponent that becomes purely imaginary in the presence of a four-body Efimov effect. Using rotational invariance in momentum space, it is found that the allowed values of s are such that M(s) has a zero eigenvalue; here the operator M(s), that depends on the total angular momentum l, acts on functions of two real variables (the cosine of the angle between two wave vectors and the logarithm of the ratio of their moduli), and we write it explicitly in terms of an integral matrix kernel. We have performed a spectral analysis of M(s), analytical and for an arbitrary imaginary s for the continuous spectrum and numerical and limited to s = 0 and l <= 12 for the discrete spectrum. We conclude that no eigenvalue of M(0) crosses zero over the mass ratio interval alpha is an element of [1; 13.6069 ... ], even if, in the parity sector (-1)(l), the continuous spectrum of M(s) has everywhere a zero lower border. As a consequence, there is no possibility of a four-body Efimov effect for the 2 + 2 fermions. We also enunciated a conjecture for the fourth virial coefficient of the unitary spin-1/2 Fermi gas, inspired from the known analytical form of the third cluster coefficient and involving the integral over the imaginary s axis of s times the logarithmic derivative of the determinant of M(s) summed over all angular momenta. The conjectured value is in contradiction with the experimental results.
Scientific journal, English - The third virial coefficient of a two-component unitary Fermi gas across an Efimov-effect threshold
Chao Gao; Shimpei Endo; Yvan Castin
EPL, EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, 109, 1, 16003, Jan. 2015, Peer-reviwed, We consider a mixture of two single-spin-state fermions with an interaction of negligible range and infinite s-wave scattering length. By varying the mass ratio alpha across alpha(c) similar or equal to 13.6069 one can switch on and off the Efimov effect. We determine analytically the third cluster coefficient of the gas. We show that it is a smooth function of alpha across alpha(c) since, unexpectedly, the three-body parameter characterizing the interaction is relevant even on the non-Efimovian side alpha < alpha(c). Copyright (C) EPLA, 2015
Scientific journal, English - Physical origin of the universal three-body parameter in atomic Efimov physics
Pascal Naidon; Shimpei Endo; Masahito Ueda
PHYSICAL REVIEW A, AMER PHYSICAL SOC, 90, 2, 022106, Aug. 2014, Peer-reviwed, We address the microscopic origin of the universal three-body parameter that fixes the spectrum of three-atom systems in the Efimov regime. We identify it with the van der Waals two-body correlation, which causes the three-atom system to deform when the three atoms come within the distance of the van der Waals length, effectively preventing them from coming closer due to the kinetic-energy cost associated with three-body deformation. This deformation mechanism explains the universal ratio of the scattering length at the triatomic resonance to the van der Waals length observed in several experiments and confirmed by numerical calculations.
Scientific journal, English - Microscopic Origin and Universality Classes of the Efimov Three-Body Parameter
Pascal Naidon; Shimpei Endo; Masahito Ueda
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 112, 10, 105301, Mar. 2014, Peer-reviwed, The low-energy spectrum of three particles interacting via nearly resonant two-body interactions in the Efimov regime is set by the so-called three-body parameter. We show that the three-body parameter is essentially determined by the zero-energy two-body correlation. As a result, we identify two classes of two-body interactions for which the three-body parameter has a universal value in units of their effective range. One class involves the universality of the three-body parameter recently found in ultracold atom systems. The other is relevant to short-range interactions that can be found in nuclear physics and solid-state physics.
Scientific journal, English - Scattering and Bound States of two Polaritons in an Array of Coupled Cavities
Chuan-zhou Zhu; Shimpei Endo; Pascal Naidon; Peng Zhang
FEW-BODY SYSTEMS, SPRINGER WIEN, 54, 11, 1921-1930, Nov. 2013, Peer-reviwed, We develop an analytical approach for calculating the scattering and bound states of two polaritons in a one-dimensional (1D) infinite array of coupled cavities, with each cavity coupled to a two-level system. We find that in such a system a contact interaction between two polaritons is induced by the non-linearity of the Jaynes-Cummigs Hamiltonian. We then solve the two-polariton problem with zero center-of-mass momentum, and find 1D scattering resonances. Our results are relevant to the transport of two polaritons, and are helpful for the investigation of many-body physics in a dilute gas of polaritons in a 1D cavity array.
Scientific journal, English - Crossover trimers connecting continuous and discrete scaling regimes
Shimpei Endo; Pascal Naidon; Masahito Ueda
Lead, PHYSICAL REVIEW A, AMER PHYSICAL SOC, 86, 6, 062703, Dec. 2012, Peer-reviwed, For a system of two identical fermions and one distinguishable particle interacting via a short-range potential with a large s-wave scattering length, the Efimov trimers and Kartavtsev-Malykh trimers exist in different regimes of mass ratio. The Efimov trimers are known to exhibit a discrete scaling invariance, while the Kartavtsev-Malykh trimers feature a continuous one. We point out that a third type of trimer, "crossover trimers," exists universally regardless of short-range details of the potential. These crossover trimers have neither discrete nor continuous scaling invariance. We show that the crossover trimers continuously connect the discrete and continuous scaling regimes as the mass ratio and the scattering length are varied. We identify the regions for the Kartavtsev-Malykh trimers, Efimov trimers, crossover trimers, and nonuniversal trimers in terms of the mass ratio and the s-wave scattering length by investigating the scaling property and universality (i.e., independence on short-range details) of the trimers. DOI: 10.1103/PhysRevA.86.062703 PACS number(s): 34.50.-s
Scientific journal, English - Universal Physics of 2+1 Particles with Non-Zero Angular Momentum
Shimpei Endo; Pascal Naidon; Masahito Ueda
Lead, FEW-BODY SYSTEMS, SPRINGER WIEN, 51, 2-4, 207-217, Nov. 2011, Peer-reviwed, The zero-energy universal properties of scattering between a particle and a dimer that involves an identical particle are investigated for arbitrary scattering angular momenta. For this purpose, we derive an integral equation that generalises the Skorniakov-Ter-Martirosian equation to the case of non-zero angular momentum. As the mass ratio between the particles is varied, we find various scattering resonances that can be attributed to the appearance of universal trimers and Efimov trimers at the collisional threshold.
Scientific journal, English - Tight-binding photonic bands in metallophotonic waveguide networks and flat bands in kagome lattices
Shimpei Endo; Takashi Oka; Hideo Aoki
Lead, PHYSICAL REVIEW B, AMER PHYSICAL SOC, 81, 11, 113104, Mar. 2010, Peer-reviwed, We propose that we can realize "tight-binding photonic bands" in metallophotonic waveguide networks, where the photonic bound states localized around the crossings of a network form a tight-binding band. The formation of bound states at the crossings is distinct from the conventional bound states at defects or virtual bound states in photonic crystals, but comes from a photonic counterpart of the zero-point states in wave mechanics. Model calculations show that the low-lying photon dispersions are indeed described accurately by the tight-binding model. To exemplify how we can exploit the tight-binding analogy for designing of photonic bands, we propose a "flat photonic band" in the kagome network, in which the photonic flat band is shown to arise with group velocities that can be as small as 1/1000 times the velocity of light in vacuum.
Scientific journal, English
MISC
- サイエンストピックス「量子少数多体問題」
遠藤晋平
Lead, Jun. 2023, 泉萩会会報, 39, 5, Japanese, Invited, Introduction commerce magazine - Anthony J. Leggett, Haruki Watanabe, Hakuto Suzuki, Yuya Tanizaki, Kota Masuda, Masaru Hongo, Shimpei Endo
Anthony J. Leggett; Haruki Watanabe; Hakuto Suzuki; Yuya Tanizaki; Kota Masuda; Masaru Hongo; Shimpei Endo
May 2012, Bussei Kenkyu, 1, 1, 011201, English, Invited, Lecture materials
Lectures, oral presentations, etc.
- 双極子相互作用する冷却原子におけるEfimov状態の挙動
大井一輝; 遠藤晋平
Oral presentation, Japanese, 日本物理学会 2025年春季大会
Mar. 2025
18 Mar. 2025- 21 Mar. 2025 - Efimov states in highly excited nuclear halos
Shimpei Endo
Oral presentation, English, 4th Franco-Japanese workshop on Few-body Problems in Physics from Atoms to Quarks
Mar. 2025
03 Mar. 2025- 07 Mar. 2025 - Efimov states in the highly excited nuclei
Shimpei Endo
Invited oral presentation, Japanese, Advancing physics at next RI Beam Factory (ADRIB25), Invited
22 Jan. 2025
22 Jan. 2025- 23 Jan. 2025 - 量子少数多体問題と量子シミュレーション
遠藤晋平
Public discourse, Japanese, COMPASS meetup, 電気通信大学, Invited
24 Oct. 2024
24 Oct. 2024- 24 Oct. 2024 - Universality of Efimov states with van der Waals interaction and dipole interaction
Shimpei Endo
Invited oral presentation, English, Beijing-Tokyo-Xi’an Joint Workshop on Quantum Matters, Invited
18 Oct. 2024
16 Oct. 2024- 20 Oct. 2024 - 3-body bound states in cold atoms; universal or non-universal?
Invited oral presentation, English, International workshop on many body interactions 2024, Invited
31 Aug. 2024
31 Aug. 2024- 31 Aug. 2024 - Dynamical invariant based shortcut to equilibration. Quantum Mpemba effect.
Shimpei Endo
Oral presentation, Japanese, 第６回冷却原子研究会「アトムの会」
01 Aug. 2024
30 Jul. 2024- 01 Aug. 2024 - 双極子相互作用する冷却原子におけるEfimov状態の普遍的挙動
大井一輝; Naidon Pascal,遠藤晋平
Oral presentation, Japanese, 第６回冷却原子研究会「アトムの会」
31 Jul. 2024
30 Jul. 2024- 01 Aug. 2024 - 相互作用の強い量子少数～多体系の普遍的挙動
遠藤晋平
Public discourse, Japanese, Invited
20 May 2024
20 May 2024- 20 May 2024 - Universality of Efimov states in cold atoms with dipole interaction
Kazuki Oi; Shimpei Endo
Poster presentation, English, Ultracold Atoms Japan 2024
09 Apr. 2024
09 Apr. 2024- 12 Apr. 2024 - 原子核励起状態におけるエフィモフ状態
遠藤晋平、田中純貴
Oral presentation, Japanese, 日本物理学会春季大会
20 Mar. 2024
18 Mar. 2024- 21 Mar. 2024 - 双極子相互作用する冷却原子におけるEfimov状態の普遍的挙動
大井一輝き; 遠藤晋平
Oral presentation, Japanese, 日本物理学会春季大会
19 Mar. 2024
18 Mar. 2024- 21 Mar. 2024 - Surprisingly large s-wave scattering length and Efimov states in the excited nuclei
Shimpei Endo
Public discourse, Japanese, RCNPコロキウム, Invited
29 Feb. 2024
29 Feb. 2024- 29 Feb. 2024 - Equation of state of the unitary Fermi gas revealed by the 4th order virial expansion
Shimpei Endo
Poster presentation, Japanese, 東北大学学際科学フロンティア研究所 10周年記念式典, Invited
19 Feb. 2024
19 Feb. 2024- 19 Feb. 2024 - Universality of Efimov states in cold atoms and nuclear physics
Shimpei Endo
Invited oral presentation, English, UEC-SAARC Symposium on Emerging Technologies (USSET 2023), Invited
07 Dec. 2023
06 Dec. 2023- 07 Dec. 2023 - ミクロな世界たちをつなぐ、量子少数多体問題の普遍性
遠藤晋平
Public discourse, Japanese, 物理工学プログラム談話会, Invited
30 Nov. 2023
30 Nov. 2023- 30 Nov. 2023 - Exciting nuclei for the Efimov physics
遠藤晋平
Invited oral presentation, Japanese, 第9回クラスター階層領域研究会, Invited
22 Sep. 2023
22 Sep. 2023- 23 Sep. 2023 - Efimov physics in the sub-threshold excited nuclei
Shimpei Endo
Invited oral presentation, RIBF Users Meeting 2023, Invited
07 Sep. 2023
06 Sep. 2023- 07 Sep. 2023 - Theoretical reserah of 3-body Fermi system with dipole interaction
大井一輝; 遠藤晋平
Poster presentation, Japanese, 第５回冷却原子研究会「アトムの会」
02 Aug. 2023
02 Aug. 2023- 03 Aug. 2023 - Universality of resonantly interacting few--body systems
理論核物理研究会; 現代核物理の広がりと展望
Invited oral presentation, 九州大学 理論核物理研究会 「現代核物理の広がりと展望」, Invited
20 Jul. 2023
19 Jul. 2023- 21 Jul. 2023 - Three-body systems in cold atoms and nuclei
Shimpei Endo
Oral presentation, English, Joint RIKEN-Tohoku workshop
11 May 2023
11 May 2023- 12 May 2023 - パネルディスカッション「Open Systems」
Nominated symposium, 第 4 回若手放談会, Invited
15 Mar. 2023
15 Mar. 2023- 17 Mar. 2023 - Equilibrium and dynamical properties of the unitary Fermi gases
Shimpei Endo
Oral presentation, 3rd France-Japan Workshop "Clusters in quantum systems: from atoms to nuclei and hadrons"
01 Mar. 2023
27 Feb. 2023- 03 Mar. 2023 - ユニタリー極限近傍の少数多体系の普遍的挙動
Invited oral presentation, Japanese, 量子クラスター第8回領域研究会, Invited
11 Feb. 2023
09 Feb. 2023- 11 Feb. 2023 - Equation of state of the unitary Fermi gas revealed by the 4th order virial expansion
Shimpei Endo; Yvan Castin
Poster presentation, International symposium on Clustering as a Window on the Hierarchical Structure of Quantum Systems (CLUSHIQ2022)
2022
27 Oct. 2022- 03 Nov. 2022 - Equation of state of the unitary Fermi gas revealed by the 4th order virial expansion
Shimpei Endo; Yvan Castin
Poster presentation, 第4回冷却原子研究会「アトムの会」
21 Sep. 2022
21 Sep. 2022- 22 Sep. 2022 - Fourth order virial expansion in a mass-imblanced unitary Fermi gas
Shimpei Endo; Yvan Castin
Oral presentation, Japanese, 日本物理学会秋季大会
13 Sep. 2022
12 Sep. 2022- 15 Sep. 2022 - 冷却原子におけるエフィモフ状態とその普遍性
遠藤晋平
Invited oral presentation, 基研国内モレキュール型研究会「少数系の量子ダイナミクス」, Invited
23 Aug. 2022
22 Aug. 2022- 26 Aug. 2022 - Equation of state of the unitary Fermi gas revealed by the 4th order virial expansion
Shimpei Endo; Yvan Castin
Poster presentation, Japanese, 29th International Conference on Low Temperature Physics (LT29)
19 Aug. 2022
18 Aug. 2022- 24 Aug. 2022 - Unitary Fermi Gas: Equivalence of its dissipative and dissipationless dynamics + High temperature EOS with virial expansion
Shimpei Endo
Oral presentation, English, Joint RIKEN-Tohoku workshop
27 Apr. 2022
27 Apr. 2022- 28 Apr. 2022 - Equivalence of dissipative and dissipationless dynamics of the unitary Fermi gas
Shimpei Endo
Invited oral presentation, English, Ultracold Atoms Japan 2022, Invited
13 Apr. 2022
12 Apr. 2022- 14 Apr. 2022 - Equivalence of dissipative and dissipationless quantum many-body dynamics
Shimpei Endo
Invited oral presentation, English, 第７回クラスター階層領域研究会, Invited
28 Dec. 2021
27 Dec. 2021- 28 Dec. 2021 - 量子散逸ダイナミクスに関する厳密な関係式とユニタリー気体への応用
遠藤晋平; 時枝正明
Oral presentation, 日本物理学会秋季大会
14 Sep. 2021
14 Sep. 2021- 17 Sep. 2021 - ユニタリーフェルミ気体の量子散逸ダイナミクスの、散逸なしモデルへの厳密なマッピング
遠藤晋平
Oral presentation, 第3回冷却原子研究会「アトムの会」
10 Aug. 2021
10 Aug. 2021- 11 Aug. 2021 - 原子核ハロー状態のエフィモフ理論による統⼀的記述
遠藤晋平
Public symposium, 第６回クラスター階層領域研究会, Invited
14 Jun. 2021
14 Jun. 2021- 19 Jun. 2021 - Halo 3-body systems of cold atoms and nuclear systems
Shimpei Endo
Oral presentation, Joint Tohoku-RIKEN internal Workshop, Invited
20 May 2021
20 May 2021- 21 May 2021 - Universality of quantum systems: Are atoms spherical?
Shimpei Endo
Oral presentation, FRIS Annual Meeting 2021/1st TI-FRIS International Symposium
23 Mar. 2021
23 Mar. 2021- 24 Mar. 2021 - 冷却原子における3体相関
遠藤晋平
Public discourse, 第４回「量子クラスターで読み解く物質階層構造」インフォーマルミーティング, Invited
19 Mar. 2021
19 Mar. 2021- 19 Mar. 2021 - Universal description of neutron-rich nuclei and cold atoms by Efimov theory
Taiki Nishiura; Shimpei Endo
Oral presentation, Japanese Physical Society Meeting
12 Mar. 2021
12 Mar. 2021- 15 Mar. 2021 - Universality of bosonic few-body clusters in cold atoms
Shimpei Endo
Keynote oral presentation, Asia-Pacific conference on few-body problems in physics (APFB2020), Invited
04 Mar. 2021
01 Mar. 2021- 05 Mar. 2021 - Are atoms spherical?
Are atoms spherical?
Public discourse, SNP group seminar, RIKEN, Invited
24 Feb. 2021
24 Feb. 2021- 24 Feb. 2021 - 量子少数多体問題のユニバーサリティとEfimov状態の物理
遠藤晋平
Public discourse, 東京工業大学セミナー, Invited
07 Dec. 2020
07 Dec. 2020- 07 Dec. 2020 - Universality of few-body Efimov clusters and their applications to many-body systems
遠藤晋平
Oral presentation, 原子核・ハドロン物理 2020, Invited
25 Sep. 2020
02 Oct. 2020- 02 Oct. 2020 - 3-body states in cold atoms and their effects on many-body physics
Shimpei Endo
Oral presentation, 第5回クラスター階層領域研究会
24 Sep. 2020
24 Sep. 2020- 25 Sep. 2020 - Few- and many-body physics in unitary gases
Shimpei Endo
Invited oral presentation, Japanese Physical Society Meeting, Invited
09 Sep. 2020
08 Sep. 2020- 11 Sep. 2020 - Universal behaviour of two-component Bose gas
Taiki Nishiura; Shimpei Endo
Oral presentation, Japanese Physical Society Meeting
08 Sep. 2020
08 Sep. 2020- 11 Sep. 2020 - Universality of quantum few- and many-body systems; investigating solids and the universe by cold atoms
Shimpei Endo
Public discourse, GPPU Lecture & Tohoku Forum for Creativity; School on Modern Physics Tohoku, Invited
31 Aug. 2020
31 Aug. 2020- 01 Sep. 2020 - 3-body bound states in cold atoms and their effects on many-body physics
Shimpei Endo
Oral presentation, Mini workshop : Three-Body Forces and Related Topics
19 Aug. 2020
19 Aug. 2020- 19 Aug. 2020 - 二成分Bose系におけるEfimov状態の普遍的挙動
西浦大樹; 遠藤 晋平
Oral presentation, 日本物理学会年次大会
18 Mar. 2020
16 Mar. 2020- 19 Mar. 2020 - 3成分Fermi気体の状態方程式におけるEfimov状態の効果
遠藤 晋平; 田島裕之
Oral presentation, 日本物理学会年次大会
18 Mar. 2020
16 Mar. 2020- 19 Mar. 2020 - ユニタリー原子気体における量子少数多体問題の研究
遠藤 晋平
Invited oral presentation, 日本物理学会年次大会, Invited
17 Mar. 2020
16 Mar. 2020- 19 Mar. 2020 - 冷却原子におけるクラスターの普遍性：現状と展望
遠藤 晋平
Public discourse, 新学術領域研究「量子クラスターで読み解く物質の階層構造」スクール, Invited
03 Mar. 2020
02 Mar. 2020- 04 Mar. 2020 - パネルディスカッション「冷やすとは？」
遠藤 晋平
Nominated symposium, 第３回若手放談会：エキゾチック核物理の将来, Invited
20 Feb. 2020
19 Feb. 2020- 21 Feb. 2020 - Universality of few-body clusters and their applications to many-body systems
Shimpei Endo
Oral presentation, 2nd workshop ``Clusters in quantum systems: from atoms to nuclei and hadrons"
27 Jan. 2020
27 Jan. 2020- 31 Jan. 2020 - 冷却原子と原子核における量子三体系とその普遍性
西浦大樹; 遠藤晋平
Poster presentation, Japanese, 第1回 冷却原子研究会「アトムの会」
18 Sep. 2019
18 Sep. 2019- 20 Sep. 2019 - Universal few-body clusters in cold atoms
Shimpei Endo
Oral presentation, Japanese, 第1回 冷却原子研究会「アトムの会」, Domestic conference
18 Sep. 2019 - Universal few-body clusters in cold atoms
Shimpei Endo
Keynote oral presentation, English, 24th European conference on few-body problems in physics, Invited, International conference
02 Sep. 2019 - Few-body aspects of cold atoms
Shimpei Endo
Invited oral presentation, Japanese, Few Body Systems in Hadron, Nuclear, Atomic and Molecular Physics, Invited, Domestic conference
09 Aug. 2019 - Few-body aspects of cold atoms
Shimpei Endo
Invited oral presentation, English, New aspects of few-nucleon systems and related topics, Invited, Domestic conference
07 Jul. 2019 - Effects of higher-angular-momentum channels in 3 identical Bose systems
Shimpei Endo
Oral presentation, Japanese, Japanese Physical Society Annual Meeting, Domestic conference
14 Mar. 2019 - Universal few-body physics and clusters with ultracold atoms
Shimpei Endo
Invited oral presentation, Japanese, 第2回RIBF若手放談会, Invited, Domestic conference
18 Feb. 2019 - Feshbach resonance in cold atoms: theoretical minimum
Shimpei Endo
Invited oral presentation, Japanese, 第3回「物質階層を横断する会」, Invited, Domestic conference
12 Feb. 2019 - Universal few-body clusters in ultracold atoms
Shimpei Endo
Oral presentation, English, Clusters in quantum systems: from atoms to nuclei and hadrons, Domestic conference
28 Jan. 2019 - Universal few-body physics in cold atoms
Shimpei Endo
Invited oral presentation, English, Reimei Workshop: Universal physics in Many-Body Quantum Systems -- From Atoms to Quarks --, Invited, International conference
12 Dec. 2018 - 少数多体系の研究の現状と今後
遠藤晋平
Invited oral presentation, Japanese, 第0回冷却原子討論会, Domestic conference
21 Sep. 2018 - Universality of strongly interacting quantum systems: From few-body to many-body
Shimpei Endo
Oral presentation, 第3回FRIS若手研究者学際融合領域研究会 Fris Retreat, Domestic conference
03 Sep. 2018 - Universal few-body correlations in a Bose polaron
Shimpei Endo
Poster presentation, English, Humboldt Kolleg“Controlling quantum matter: From ultracold atoms to solids”, International conference
31 Jul. 2018 - Universal few-body correlations in a Bose polaron
Shimpei Endo
Poster presentation, English, 26th International Conference on Atomic Physics (ICAP2018), International conference
22 Jul. 2018 - Universality of strongly interacting quantum systems: From few-body to many-body
Shimpei Endo
Invited oral presentation, English, Recent progress of nuclear structure and reaction theory, Domestic conference
26 Apr. 2018
Courses
- Complex Analysis
Apr. 2024 - Present
The University of Electro-Communications - Advanced Programming
Apr. 2024 - Present
The University of Electro-Communications - Programming
Oct. 2023 - Mar. 2025
The University of Electro-Communications - 電磁気学II演習
Apr. 2023 - Jul. 2023
東北大学 - Physics Seminar (3yr undergrad.)
Oct. 2022 - Mar. 2023
Tohoku University - Classical MechanicsII
Oct. 2022 - Mar. 2023
Tohoku University - 全学教育科目「基礎ゼミ」
Jun. 2021 - Aug. 2021
東北大学 - Null
Jun. 2019 - Aug. 2019
Tohoku University - Universality of few-body quantum systems and Efimov physics
Feb. 2019 - Feb. 2019
Yukawa Institute for Theoretical Physics, Kyoto University
Research Themes
- エフィモフ状態の三体パラメータの普遍性の破綻機構
遠藤晋平
松尾学術振興財団, 松尾学術研究助成, Principal investigator
Dec. 2024 - Mar. 2026 - Universal Quantum Dynamics of Impurity Particles in Strongly Correlated Matter
赤松 幸尚; 本郷 優; 遠藤 晋平
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Osaka University, Grant-in-Aid for Scientific Research (B), Coinvestigator, 23K25870
Apr. 2023 - Mar. 2026 - 強相関物質における不純物粒子の量子ダイナミクスの普遍性の研究
赤松 幸尚,本郷 優
日本学術振興会, 科学研究費助成事業 基盤研究(B), 大阪大学, 基盤研究(B), Coinvestigator, 23H01174
Apr. 2023 - Mar. 2026 - a
遠藤 晋平
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Tohoku University, Grant-in-Aid for Scientific Research (C), Principal investigator, 22K03492
Apr. 2022 - Mar. 2026 - 原子核ハロー状態のエフィモフ理論による統一的記述
遠藤 晋平
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Tohoku University, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Principal investigator, 21H00116
Apr. 2021 - Mar. 2023 - 量子少数クラスターにより発現する普遍的な量子多体物性
Shimpei Endo
JSPS (KAKENHI), Grant-in-Aid for Research Activity Start-up, Principal investigator
Aug. 2018 - Mar. 2020 - 冷却原子気体のBEC-BCSクロスオーバーにおける多体効果の理論的研究
遠藤 晋平
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows, The University of Tokyo, Grant-in-Aid for JSPS Fellows, Principal investigator, 散乱長が大きな3粒子系では、離散スケーリング則を示す3粒子束縛状態が普遍的に現れ、Efimov状態とよばれる。Efimov状態のエネルギースケールを決定する重要なパラメータとして3体パラメータがある。近年、3体パラメータが普遍的に振舞うことが冷却原子気体の実験で発見された。昨年までの研究で、私は冷却原子系特有のvan der Waals型相互作用をする系について、3体パラメータが普遍的に振舞うことの物理的起源を解明した。本年度の研究では、vall der Waals型以外の様々な相互作用をする3粒子問題を解き、3体パラメータが普遍性がvan der Waals型以外の様々な相互作用をする系について普遍的に成立することを発見した。また、相互作用の遠方での減衰の速さに依存して、3体パラメータのUniversality classの分類が可能なことを発見し、これらの成果をPhysical Review Letters誌に発表した。 Efimov状態は冷却原子気体以外にも、^4Heクラスター、中性子過剰原子核、マグノン等で現れる可能性が示唆されており、本研究はこれら様々な系での少数系の理解に本研究が大きく貢献するものと期待される。また、本研究は相互作用が散乱長が大きな領域でのボソン系の振舞いを研究したものであるが、Fermion系においてもEfimv状態が現れうることが知られており、Boson系、Fermion系双方の少数・多体系の振舞いの理解にも有用となることが期待される。 また質量インバランスのある系における3体パラメータの振舞いに関する研究も行った。その結果、同種粒子系の場合と類似の形をしたHyper-radial repulsionが現れることを発見し、3体パラメータが普遍的に振舞う可能性があることを見出した。, 11J07049
2011 - 2013
Academic Contribution Activities
- Public Lecture: Quantum Field Theory: a Universal Language
Academic society etc, Planning etc, 主催者, 27 Sep. 2024 - 27 Sep. 2024 - 滞在型研究会 Junior Reserach Program
Academic society etc, Planning etc, 東北大学知の創出センター(organizer: 遠藤晋平), 26 Aug. 2024 - 27 Sep. 2024 - 第６回冷却原子研究会「アトムの会」
Academic society etc, Planning etc, 世話人, 30 Jul. 2024 - 01 Aug. 2024 - 第５回冷却原子研究会「アトムの会」
Academic society etc, Planning etc, 世話人, 02 Aug. 2023 - 03 Aug. 2023
