792 citations · 5.2k across the 61 of their papers we have counts for
61 papers
Revisiting electromagnetic response of superconductors in mean-field approximation
Chang-geun Oh, Haruki Watanabe
In the standard mean-field treatment of superconductors, the electron-electron interactions are assumed to be written in terms of local density operators. However, more general int…
Spontaneous symmetry breaking without ground state degeneracy in generalized -state clock model
Yaozong Hu, Haruki Watanabe
Spontaneous symmetry breaking is ubiquitous phenomenon in nature. One of the defining features of symmetry broken phases is that the large system size limit and the vanishing exter…
Drude weights in one-dimensional systems with a single defect
Kazuaki Takasan, Masaki Oshikawa, Haruki Watanabe
Ballistic transport of a quantum system can be characterized by Drude weight, which quantifies the response of the system to a uniform electric field in the infinitely long timesca…
Ground state degeneracy on torus in a family of toric code
Haruki Watanabe, Meng Cheng, Yohei Fuji
Topologically ordered phases in dimensions are generally characterized by three mutually-related features: fractionalized (anyonic) excitations, topological entanglement entr…
Classification of time-reversal symmetric topological superconducting phases for conventional pairing symmetries
Seishiro Ono, Ken Shiozaki, Haruki Watanabe
Based on a recently developed framework, we conduct classifications of time-reversal symmetric topological superconductors with conventional pairing symmetries. Our real-space appr…
Vanishing and non-vanishing persistent currents of various conserved quantities
Hirokazu Kobayashi, Haruki Watanabe
For every conserved quantity written as a sum of local terms, there exists a corresponding current operator that satisfies the continuity equation. The expectation values of curren…
Fractional hinge and corner charges in various crystal shapes with cubic symmetry
Katsuaki Naito, Ryo Takahashi, Haruki Watanabe +1
Higher-order topological insulators host gapless states on hinges or corners of three-dimensional crystals. Recent studies suggested that even topologically trivial insulators may…
The Bloch theorem in the presence of an additional conserved charge
Haruki Watanabe
The Bloch theorem is a general theorem restricting the persistent current associated with a conserved U(1) charge in a ground state or in a thermal equilibrium. It gives an upper b…
Bloch oscillations in the spin-1/2 XXZ chain
Yankang Liu, Yohei Fuji, Haruki Watanabe
Under a perfect periodic potential, the electric current density induced by a constant electric field may exhibit nontrivial oscillations, so-called Bloch oscillations, with an amp…
High-throughput Investigations of Topological and Nodal Superconductors
Feng Tang, Seishiro Ono, Xiangang Wan +1
The theory of symmetry indicators has enabled database searches for topological materials in normal conducting phases, which has led to several encyclopedic topological material da…
Adiabatic transport in one-dimensional systems with a single defect
Kazuaki Takasan, Masaki Oshikawa, Haruki Watanabe
The adiabatic transport properties of U(1) invariant systems are determined by the dependence of the ground state energy on the twisted boundary condition. We examine a one-dimensi…
Off-Diagonal Long-Range Order Implies Vanishing Charge Gap
Hal Tasaki, Haruki Watanabe
For a large class of quantum many-body systems with U(1) symmetry, we prove a general inequality that relates the (off-diagonal) long-range order with the charge gap. For a system…
Fractional corner magnetization of collinear antiferromagnets
Haruki Watanabe, Yasuyuki Kato, Hoi Chun Po +1
Recent studies revealed that the electric multipole moments of insulators result in fractional electric charges localized to the hinges and corners of the sample. We here explore t…
Fractional Corner Charge of Sodium Chloride
Haruki Watanabe, Hoi Chun Po
Recent developments in higher-order topological phases have elucidated on the relationship between nontrivial multipole moments in the bulk and the emergence of fractionally quanti…
Corner charge and bulk multipole moment in periodic systems
Haruki Watanabe, Seishiro Ono
A formula for the corner charge in terms of the bulk quadrupole moment is derived for two-dimensional periodic systems. This is an analog of the formula for the surface charge dens…
qeirreps: an open-source program for Quantum ESPRESSO to compute irreducible representations of Bloch wavefunctions
Akishi Matsugatani, Seishiro Ono, Yusuke Nomura +1
Bloch wavefunctions in solids form a representation of crystalline symmetries. Recent studies revealed that symmetry representations in band structure can be used to diagnose the t…
On the general properties of non-linear optical conductivities
Haruki Watanabe, Yankang Liu, Masaki Oshikawa
The optical conductivity is the basic defining property of materials characterizing the current response toward time-dependent electric fields. In this work, following the approach…
Generalized -Sum Rules and Kohn formulas on Non-linear Conductivities
Haruki Watanabe, Masaki Oshikawa
The -sum rule and the Kohn formula are well-established general constraints on the electric conductivity in quantum many-body systems. We present their generalization to non-lin…
Proof of the absence of long-range temporal orders in Gibbs states
Haruki Watanabe, Masaki Oshikawa, Tohru Koma
We address the question whether time translation symmetry can be spontaneously broken in a quantum many-body system. One way of detecting such a symmetry breaking is to examine the…
Refined symmetry indicators for topological superconductors in all space groups
Seishiro Ono, Hoi Chun Po, Haruki Watanabe
Topological superconductors are exotic phases of matter featuring robust surface states that could be leveraged for topological quantum computation. A useful guiding principle for…
Quantum Quench and -Sum Rules on Linear and Non-linear Conductivities
Masaki Oshikawa, Haruki Watanabe
Considering a quench process in which an electric field pulse is applied to the system, "-sum rule" for the conductivity for general quantum many-particle systems is derived. It…
Geometric orbital magnetization in adiabatic processes
Luka Trifunovic, Seishiro Ono, Haruki Watanabe
We consider periodic adiabatic processes of gapped many-body spinless electrons. We find an additional contribution to the orbital magnetization due to the adiabatic time evolution…
A proof of the Bloch theorem for lattice models
Haruki Watanabe
The Bloch theorem is a powerful theorem stating that the expectation value of the U(1) current operator averaged over the entire space vanishes in large quantum systems. The theore…
Counting Rules of Nambu-Goldstone Modes
Haruki Watanabe
When global continuous symmetries are spontaneously broken, there appear gapless collective excitations called Nambu-Goldstone modes (NGMs) that govern the low-energy property of t…