Related papers: Chiral charge as hidden order parameter in URu$_2$…
The observation of chirality is ubiquitous in nature. Contrary to intuition, the population of opposite chiralities is surprisingly asymmetric at fundamental levels. Examples range from parity violation in the subatomic weak force to the…
We discuss possible approaches to the problem of the URu2Si2 "Hidden Order" (HO) which remains unsolved after tremendous efforts of researches. Suppose there is no spatial symmetry breaking at the HO transition temperature and solely the…
We have investigated the nature of the competition between hidden order and antiferromagnetic (AF) order in URu_2Si_2 by performing the neutron scattering experiments under hydrostatic-pressure P, uniaxial-stress sigma, and Rh-substitution…
The 2D pair-condensate is characterized by a fluctuating chiral charge ordered state with a "checkerboard" pattern in the CuO_2 planes and with an alternating supermodulation along the c-axis in such a way that the adjacent layers are…
We discuss noncollinear magnetic phenomena whose local order parameter is characterized by more than one spin vector. By focusing on the simple cases of 2D triangular and 3D pyrochlore lattices, we demonstrate that their low-energy theories…
This paper reports recent progress of ultrasonic measurements on URu$_2$Si$_2$, including ultrasonic measurements under hydrostatic pressure, in pulsed-magnetic fields, and the effect of Rh-substitution. The observed changes of the elastic…
This Topical Review describes the multitude of unconventional behaviors in the hidden order, heavy fermion, antiferromagnetic and superconducting phases of the intermetallic compound URu$_2$Si$_2$ when tuned with pressure, magnetic field,…
The hidden order (HO) in URu2Si2 has been determined as a high rank multipole formed by itinerant 5f-electrons with distinct orbital structure imposed by the crystalline electric field. Because this can lead to a considerable number of…
The topological order of a (2+1)D topological phase of matter is characterized by its chiral central charge and a unitary modular tensor category that describes the universal fusion and braiding properties of its anyonic quasiparticles. I…
Spin chirality has generated great interest recently both from possible applications to flux phases and intrinsically, as an example of a several-site magnetic order parameter that can be long-ranged even where simpler order parameters are…
In 1T-TaS2, the nearly-commensurate charge density wave (NC-CDW) exhibits emergent chirality, a property of interest for technological applications such as memory. We study the relationship between chirality and topological defects using…
I study the scalar representations of the electroweak group of the Standard Model, with a special emphasis on their chiral properties and on their behaviour by the discrete symmetries P and CP. A gauge theory for J=0 mesons naturally…
The chiral central charge $c_-$ is a key topological invariant of the edge characterizing the bulk two-dimensional chiral topological order, but its direct evaluation in microscopic spin models has long been a challenge, especially for…
We have made extensive reciprocal space maps in the heavy-fermion superconductor URu2Si2 using high-resolution time-of-flight single-crystal neutron diffraction to search for signs of a hidden order parameter related to the 17.5 K phase…
Despite fermion doubling, a two-dimensional quasi-relativistic spin-1/2 system can still lead to true fractionalization of electrical charge, when a massive ordered phase supports a "half-vortex". Such topological defect is possible when…
Motivated by the recent discovery of broken four-fold symmetry in the hidden order phase of URu$_2$Si$_2$[R. Okazaki et al., Science {\bf 331}, 439 (2011)], we examine a scenario of a spin nematic state as a possible candidate of the hidden…
We propose a candidate for the hidden order in URu2Si2: a rank-5 E type spin density wave between Uranium 5f crystal field doublets breaking time reversal and lattice tetragonal symmetry in a manner consistent with recent torque…
Unconventional superconductivity (SC) characterized by multi-fermion orderings has attracted substantial attention. However, previous studies have largely focused on 2D systems or 3D systems with effective 2D symmetries. Here, we…
Hidden order in URu$_2$Si$_2$ has remained a mystery now entering its 4th decade. The importance of resolving the nature of the hidden order has stimulated extensive research. Here we present a detailed characterization of different surface…
Novel electronic states resulting from entangled spin and orbital degrees of freedom are hallmarks of strongly correlated f-electron systems. A spectacular example is the so-called 'hidden-order' phase transition in the heavy-electron metal…