Publications

[43] High-field magnetism of the spin-1/2 two-leg-ladder antiferromagnet Cu(DEP)Cl2 under high pressure

T. Morimoto, E. Morikawa, K. Nihongi, T. Kida, Y. Narumi, Z. Honda, S. Furukawa, Y. Uwatoko, K. Kindo, M. Hagiwara, J. Phys. Soc. Jpn. 94, 024701 (2025) [6 pages]

[42] Phase diagram of a spin-1/2 Heisenberg ladder with a chirality-chirality interaction

M. Fontaine and S. Furukawa, J. Phys. Soc. Jpn. 93, 124710 (2024) [13 pages; open access]

[41] System-environment entanglement phase transitions

Y. Ashida, S. Furukawa, and M. Oshikawa, Phys. Rev. B 110, 094404 (2024) [20 pages]

(Measurement-induced system-environment entanglement in a Tomonaga-Luttinger liquid; see also [6])

[40] Symmetry, topology, duality, chirality, and criticality in a spin-1/2 XXZ ladder with a four-spin interaction

M. Fontaine, K. Sugimoto, and S. Furukawa, Phys. Rev. B 109, 134413 (2024) [21 pages]

[39] Ground-state phase diagram of a spin-1/2 frustrated XXZ ladder

T. Ogino, R. Kaneko, S. Morita, and S. Furukawa, Phys. Rev. B 106, 155106 (2022) [17 pages]

[38] Vortex lattices in binary Bose-Einstein condensates: Collective modes, quantum fluctuations, and intercomponent entanglement

T. Yoshino, S. Furukawa, and M. Ueda, J. Phys. B: At. Mol. Opt. Phys. 55, 105302 (2022) [22 pages; open access]

[37] Symmetry-protected topological phases and competing orders in a spin-1/2 XXZ ladder with a four-spin interaction

T. Ogino, S. Furukawa, R. Kaneko, S. Morita, and N. Kawashima, Phys. Rev. B 104, 075135 (2021) [16 pages]

(Bosonization and numerical approaches to SPT and ordered phases in spin-1/2 ladders; see also [35,39,40,42])

[36] Intercomponent entanglement entropy and spectra in binary Bose-Einstein condensates

T. Yoshino, S. Furukawa, and M. Ueda, Phys. Rev. A 103, 043321 (2021) [14 pages]

[35] Continuous phase transition between Neel and valence bond solid phases in a J-Q-like spin ladder system

T. Ogino, R. Kaneko, S. Morita, S. Furukawa, and N. Kawashima, Phys. Rev. B 103, 085117 (2021) [12 pages]

[34] Magnetoelastic study on the frustrated quasi-one-dimensional spin-1/2 magnet LiCuVO4

A. Miyata, T. Hikihara, S. Furukawa, R. K. Kremer, S. Zherlitsyn, J. Wosnitza, Phys. Rev. B 103, 014411 (2021) [8 pages]

[33] Continuous phase transition without gap closing in non-Hermitian quantum many-body systems

N. Matsumoto, K. Kawabata, Y. Ashida, S. Furukawa, and M. Ueda, Phys. Rev. Lett. 125, 260601 (2020) [7 pages and Suppl. Mat.]

[32] Probing XY phase transitions in a Josephson junction array with tunable frustration

R. Cosmic, K. Kawabata, Y. Ashida, H. Ikegami, S. Furukawa, P. Patil, J.M. Taylor, and Y. Nakamura, Phys. Rev. B 102, 094509 (2020) [10 pages]

[31] Effects of Dzyaloshinskii-Moriya interactions in volborthite: Magnetic orders and thermal Hall effect

S. Furukawa and T. Momoi, J. Phys. Soc. Jpn. 89, 034711 (2020) [19 pages; Editors' Choice; open access]

See also K. Totsuka, JPSJ News Comments 17, 03 (2020): New surprises from "bamboo baskets"

紹介記事：ボルボサイトにおけるフラストレート磁性と熱輸送現象にミクロな視点から迫る

[30] Magnetoelastic couplings in the deformed kagome quantum spin lattice of volborthite

A. Ikeda, S. Furukawa, O. Janson, Y. H. Matsuda, S. Takeyama, T. Yajima, Z. Hiroi, and H. Ishikawa, Phys. Rev. B 99, 140412(R) (2019) [5 pages]

[29] Collective modes of vortex lattices in two-component Bose-Einstein condensates under synthetic gauge fields 

T. Yoshino, S. Furukawa, S. Higashikawa, and M. Ueda, New J. Phys. 21, 015001 (2019) [23 pages]

Invited paper in Spotlight on Multicomponent Quantum Matter (open access)

[28] Quantum Hall phase diagram of two-component Bose gases: Intercomponent entanglement and pseudopotentials

S. Furukawa and M. Ueda, Phys. Rev. A 96, 053626 (2017) [12 pages]

[27] Capacity of entanglement and the distribution of density matrix eigenvalues in gapless systems

Y. O. Nakagawa and S. Furukawa, Phys. Rev. B 96, 205108 (2017) [8 pages] 

[26] Parity-time symmetric quantum critical phenomena

Y. Ashida, S. Furukawa, and M. Ueda, Nat. Commun. 8, 15791 (2017) [6 pages and Suppl. Mat.; open access] 

(Anomalous RG flow in a generalized sine-Gordon model describing open quantum systems; See also [22])

[25] Bosonic integer quantum Hall effect as topological pumping

M. Nakagawa and S. Furukawa, Phys. Rev. B 95, 165116 (2017) [9 pages; Editors' Suggestion]

[24] Devil's staircases in synthetic dimensions and gauge fields

T. Y. Saito and S. Furukawa, Phys. Rev. A 95, 043613 (2017) [9 pages]

(Simple picture for the interaction effects in synthetic dimensions)

[23] Geometrically frustrated coarsening dynamics in spinor Bose-Fermi mixtures

N. T. Phuc, T. Momoi, S. Furukawa, Y. Kawaguchi, T. Fukuhara, and M. Ueda, Phys. Rev. A 95, 013620 (2017) [12 pages]

[22] Quantum critical behavior influenced by measurement backaction in ultracold gases

Y. Ashida, S. Furukawa, and M. Ueda, Phys. Rev. A 94, 053615 (2016) [11 pages]

[21] Fractional quantum Hall states of dipolar fermions in a strained optical lattice

H. Fujita, Y. O. Nakagawa, Y. Ashida, and S. Furukawa, Phys. Rev. A 94, 043641 (2016) [12 pages]

[20] Magnetic behavior of volborthite Cu3V2O7(OH)2(H2O)2 determined by coupled trimers rather than frustrated chains

O. Janson, S. Furukawa, T. Momoi, P. Sindzingre, J. Richter, and K. Held, Phys. Rev. Lett. 117, 037206 (2016) [6 pages and Suppl. Mat.]

(A new microscopic spin model for volborthite and a scenario for a possible nematic state; See also [30,31])

[19] Excitation band topology and edge matter waves in Bose-Einstein condensates in optical lattices

S. Furukawa and M. Ueda, New J. Phys. 17, 115014 (2015) [17 pages] 

Invited paper in Focus on Topological Physics (open access)

(Application of band topology to BECs in optical lattices)

[18] Temperature-dependent interplay of Dzyaloshinskii-Moriya interaction and single-ion anisotropy in multiferroic BiFeO3

J. Jeong, M. D. Le, P. Bourges, S. Petit, S. Furukawa, S.-A. Kim, S. Lee, S-W. Cheong, and J.-G. Park, Phys. Rev. Lett. 113, 107202 (2014) [5 pages]

[17] Global phase diagram of two-component Bose gases in antiparallel magnetic fields

S. Furukawa and M. Ueda, Phys. Rev. A 90, 033602 (2014) [11 pages]

[16] Entanglement spectra between coupled Tomonaga-Luttinger liquids: Applications to ladder systems and topological phases

R. Lundgren, Y. Fuji, S. Furukawa, and M. Oshikawa, Phys. Rev. B 88, 245137 (2013) [14 pages]; Phys. Rev. B 92, 039903 (2015) [Erratum]

See also ISSP Activity Report 2013

(Simple analytical approach to entanglement spectra in topological phases and ladder systems; See also [10,36])

[15] Integer quantum Hall state in two-component Bose gases in a synthetic magnetic field

S. Furukawa and M. Ueda, Phys. Rev. Lett. 111, 090401 (2013) [5 pages and Suppl. Mat.]

(Numerical evidence for an interaction-induced SPT phase in dimensions>1; See also [25])

[14] Quantum Hall states in rapidly rotating two-component Bose gases

S. Furukawa and M. Ueda, Phys. Rev. A 86, 031604 (R) (2012) [5 pages]

[13] Ground-state phase diagram of a spin-1/2 frustrated ferromagnetic XXZ chain: Haldane dimer phase and gapped/gapless chiral phase

S. Furukawa, M. Sato, S. Onoda, and A. Furusaki, Phys. Rev. B 86, 094417 (2012) [19 pages; Editors' Suggestion]

(Detailed phase diagram of a frustrated ferromagnetic XXZ chain model relevant to edge-sharing cuprates; See also [7,9])

[12] Spin wave measurements over the full Brillouin zone of multiferroic BiFeO3 

J. Jeong, E. A. Goremychkin, T. Guidi, K. Nakajima, G. S. Jeon, S.-A. Kim, S. Furukawa, Y. B. Kim, S. Lee, V. Kiryukhin, S.-W. Cheong, and J.-G. Park, Phys. Rev. Lett. 108, 077202 (2012) [5 pages]

[11] Ferromagnetically coupled dimers on the distorted Shastry-Sutherland lattice: Application to (CuCl)LaNb2O7 

S. Furukawa, T. Dodds, and Y. B. Kim, Phys. Rev. B 84, 054432 (2011) [19 pages]

[10] Entanglement entropy between two coupled Tomonaga-Luttinger liquids

S. Furukawa and Y.B. Kim, Phys. Rev. B 83, 085112 (2011) [17 pages]; Phys. Rev. B 87, 119101 (2013) [Erratum]

[9] Chiral order and electromagnetic dynamics in one-dimensional multiferroic cuprates

S. Furukawa, M. Sato, and S. Onoda, Phys. Rev. Lett. 105, 257205 (2010) [4 pages and Supplemental Material]

See also RIKEN Research Highlight, March 4, 2011.

[8] Spontaneous population imbalance in two-component Bose and Fermi gases 

S. Takayoshi, M. Sato, and S. Furukawa, Phys. Rev. A 81, 053606 (2010) [7 pages]

[7] Unconventional Néel and dimer orders in a spin-1/2 frustrated ferromagnetic chain with easy-plane anisotropy 

S. Furukawa, M. Sato, and A. Furusaki, Phys. Rev. B 81, 094430 (2010) [9 pages; Editors' Suggestion]

[6] Shannon and entanglement entropies of one- and two-dimensional critical wave functions 

J.-M. Stéphan, S. Furukawa, G. Misguich, and V. Pasquier, Phys. Rev. B 80, 184421 (2009) [24 pages; Editors' Suggestion]

(Transfer matrix approach to universal entanglement entropy at 2D quantum Lifshitz critical points; see also [41])

[5] Mutual information and boson radius in a c=1 critical system in one dimension 

S. Furukawa, V. Pasquier, and J. Shiraishi, Phys. Rev. Lett. 102, 170602 (2009) [4 pages]

(Two-interval entanglement entropy for detailed CFT information beyond the central charge.)

[4] Quantum fluctuations of chirality in one-dimensional spin-1/2 multiferroics: gapless dielectric response from phasons and chiral solitons

S. Furukawa, M. Sato, Y. Saiga, and S. Onoda, J. Phys. Soc. Jpn. 77, 123712 (2008) [4 pages]

[3] Topological entanglement entropy in the quantum dimer model on the triangular lattice

S. Furukawa and G. Misguich, Phys. Rev. B 75, 214407 (2007) [10 pages]

(One of the earliest numerical demonstrations of topological entropy concept; See Wikipedia and nLab.)

[2] Systematic derivation of order parameters through reduced density matrices 

S. Furukawa, G. Misguich, and M. Oshikawa, Phys. Rev. Lett. 96, 047211 (2006) [4 pages]

(A general method for determining order parameters with application to topological order. See also [P2].)

[1] Thermomagnetic power and figure of merit for spin-1/2 Heisenberg chain 

S. Furukawa, D. Ikeda, and K. Sakai, J. Phys. Soc. Jpn. 74, 3241 (2005) [7 pages]: 

[P5] Competing phases in spin-1/2 J1-J2 chain with easy-plane anisotropy

M. Sato, S. Furukawa, S. Onoda, and A. Furusaki, Modern Physics Letters B 25, pp.901-908 (2011)

[Proceedings of the International Conference on Frustrated Spin Systems, Cold Atoms and Nanomaterials, a Satellite Conference of STATPHYS24; 14-16 July, 2010, Hanoi, Vietnam].

[P4] Vector spin chirality and multiferroic properties in one-dimensional spin-1/2 frustrated magnets

S. Furukawa, M. Sato, Y. Saiga, and S. Onoda, an invited paper in 2008 activity report of Supercomputer Center at the Institute for Solid State Physics 

[P3] Gapless chirality excitations in one-dimensional spin-1/2 frustrated magnets

S. Furukawa, M. Sato, Y. Saiga, and S. Onoda, Proceedings of the 9th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology - ISQM-TOKYO’08, edited by S. Ishioka and K. Fujikawa (World Scientific Co., Pte. Ltd.), p.150-153:

[P2] Reduced density matrices and topological order in a quantum dimer model

S. Furukawa, G. Misguich, and M. Oshikawa, Journal of Physics: Condensed Matter 19, 145212 (2007) [6 pages]

[Proceedings of ``Highly Frustrated Magnets (HFM)'', Osaka, August 2006].

[P1] Detection of exotic order parameters of quantum antiferromagnets through reduced density matrices

S. Furukawa, G. Misguich, and M. Oshikawa, Supplement of Progress of Theoretical Physics 159, pp. 143-147 (2005)

[Proceedings of International Symposium on Quantum Spin Systems (QSS04), Hayama, November 2004].