scholarly journals Fermi surface effect on spontaneous breaking of time-reversal symmetry in unconventional superconducting films

2015 ◽  
Vol 91 (9) ◽  
Author(s):  
Nobumi Miyawaki ◽  
Seiji Higashitani
Keyword(s):  
Fermi Surface ◽  
Time Reversal ◽  
Surface Effect ◽  
Superconducting Films ◽  
Spontaneous Breaking ◽  
Time Reversal Symmetry

scholarly journals Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor

Nature ◽  
2002 ◽  
Vol 416 (6881) ◽  
pp. 610-613 ◽  
Author(s):  
A. Kaminski ◽  
S. Rosenkranz ◽  
H. M. Fretwell ◽  
J. C. Campuzano ◽  
Z. Li ◽  
...  
Keyword(s):  
Time Reversal ◽  
Spontaneous Breaking ◽  
Time Reversal Symmetry ◽  
High Tc ◽  
Pseudogap State ◽  
High Tc Superconductor

scholarly journals Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd2As2

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw4718 ◽  
Author(s):  
J.-Z. Ma ◽  
S. M. Nie ◽  
C. J. Yi ◽  
J. Jandke ◽  
T. Shang ◽  
...  
Keyword(s):  
Long Range ◽  
Time Reversal ◽  
Spin Fluctuation ◽  
Paramagnetic Phase ◽  
Spontaneous Breaking ◽  
Time Reversal Symmetry ◽  
Energy Bands ◽  
Range Magnetic Order ◽  
Weyl Semimetal ◽  
Long Range Magnetic Order

Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi–long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.

scholarly journals TIME AND A TEMPORALLY STATISTICAL QUANTUM GEOMETRODYNAMICS

2013 ◽  
Vol 28 (14) ◽  
pp. 1330015
Author(s):  
EIJI KONISHI
Keyword(s):  
Quantum Gravity ◽  
Symmetry Breaking ◽  
Time Reversal ◽  
Hidden Variables ◽  
Spontaneous Breaking ◽  
Quantum Mechanical ◽  
Time Reversal Symmetry ◽  
Physical Origin ◽  
Variable Theory ◽  
Quantum Geometrodynamics

This paper is an exposition of the author's recent work on modeling M-theory vacua and quantum mechanical observers in the framework of a temporally statistical description of quantum geometrodynamics, including measurement processes based on the canonical theory of quantum gravity. In this paper, we deal with several fundamental issues of time: the timeless problem in canonical quantum gravity; the physical origin of state reductions; and time-reversal symmetry breaking. We first model the observers and consider the timeless problem by invoking the time reparametrization symmetry breaking in the quantum mechanical world as seen by the observers. We next construct the hidden time variable theory, using a model of the gauged and affinized S-duality symmetry in type IIB string theory, as the statistical theory of time and explain the physical origin of state reductions using it. Finally, by the extension of the time reparametrization symmetry to all of the temporal hidden variables, we treat the issue of time reversal symmetry breaking as the spontaneous breaking of this extended time reparametrization symmetry. The classification of unitary time-dependent processes and the geometrizations of unitary and nonunitary time evolutions using the language of the derived category are also investigated.

Sign in / Sign up

Export Citation Format

Share Document