792 citations · 5.2k across the 61 of their papers we have counts for
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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…
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…
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…
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…
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…
Insensitivity of bulk properties to the twisted boundary condition
Haruki Watanabe
The symmetry and the locality are the two major sources of various nontrivial statements in quantum many-body systems. We demonstrate that, in gapped phases of a U(1) symmetric Ham…
Absence of Quantum Time Crystals
Haruki Watanabe, Masaki Oshikawa
In analogy with crystalline solids around us, Wilczek recently proposed the idea of "time crystals" as phases that spontaneously break the continuous time translation into a discre…
Spontaneous breaking of continuous translational invariance
Haruki Watanabe, Tomáš Brauner
Unbroken continuous translational invariance is often taken as a basic assumption in discussions of spontaneous symmetry breaking (SSB), which singles out SSB of translational inva…