Parity Broken Chiral Spin Dynamics in Ba$_3$NbFe$_3$Si$_2$O$_{14}$

Spin parity and broken symmetry in finite spin-1/2 chains with frustrated exchange: quantum transition from high to low spin

Exact diagonalization of finite spin-1/2 chains with periodic boundary conditions is applied to the ground state (gs) of chains with ferromagnetic (F) exchange $J_1 < 0$between first neighbors, antiferromagnetic (AF) exchange $J_2 = αJ_1 > 0$between second neighbors, and axial anisotropy $0 \le Δ\le 1$. In zero field, the gs is in the $S_z = 0$ sector for the relevant parameters and is doubly degenerate at multiple points $γ_m = (α_m, Δ_m)$ in the $α$, $Δ$ plane. Degeneracy under inversion at sites or spin parity or both leads, respectively, to a bond order wave (BOW), to staggered magnetizati…

Broken Lifshitz invariance, spin waves and hydrodynamics

In this paper, based on the basic principles of thermodynamics, we explore the hydrodynamic regime of interacting Lifshitz field theories in the presence of broken rotational invariance. We compute the entropy current and discover new dissipative effects those are consistent with the principle of local entropy production in the fluid. In our analysis, we consider both the parity even as well as the parity odd sector upto first order in the derivative expansion. Finally, we argue that the present construction of the paper could be systematically identified as that of the hydrodynamic descriptio…

Odd-parity magnetoresistance in pyrochlore iridate thin films with broken time-reversal symmetry

A new class of materials termed topological insulators have been intensively investigated due to their unique Dirac surface state carrying dissipationless edge spin currents. Recently, it has been theoretically proposed that the three dimensional analogue of this type of band structure, the Weyl Semimetal phase, is materialized in pyrochlore oxides with strong spin-orbit coupling, accompanied by all-in-all-out spin ordering. Here, we report on the fabrication and magnetotransport of Eu2Ir2O7 single crystalline thin films. We reveal that one of the two degenerate all-in-all-out domain structure…

Entanglement entropy in quantum spin chains with broken parity number symmetry

Consider a generic quantum spin chain that can be mapped to free quadratic fermions via Jordan-Wigner (JW) transformation. In the presence of arbitrary boundary magnetic fields, this Hamiltonian is no longer a quadratic Hamiltonian after JW transformation. Using ancillary sites and enlarging the Hamiltonian we first introduce a bigger quadratic Hamiltonian. Then we diagonalize this enlarged Hamiltonian in its most generic form and show that all the states are degenerate because of the presence of a zero mode. The eigenstates of the original spin chain with boundary magnetic fields can be deriv…

宇称-时间对称反铁磁体中电流诱导向列狄拉克谷的输运证据

Transport evidence of current-induced nematic Dirac valleys in a parity-time-symmetric antiferromagnet

本文在宇称-时间对称反铁磁体SrMnBi2中实验观测到电流诱导狄拉克谷对称性破缺导致的非互易输运，并通过电流-磁场冷却实现f波极性调控，为反铁磁自旋电子学与谷电子学应用奠定基础。

Hydrodynamics of two-dimensional compressible fluid with broken parity: variational principle and free surface dynamics in the absence of dissipation

We consider an isotropic compressible non-dissipative fluid with broken parity subject to free surface boundary conditions in two spatial dimensions. The hydrodynamic equations describing the bulk dynamics of the fluid as well as the free surface boundary conditions depend explicitly on the parity breaking non-dissipative odd viscosity term. We construct a variational principle in the form of an effective action which gives both bulk hydrodynamic equations and free surface boundary conditions. The free surface boundary conditions require an additional boundary term in the action which resemble…

Lowest-energy states in parity-transformation eigenspaces of SO(N) spin chain

We expand the symmetry of the open finite-size SO(N) symmetric spin chain to O(N). We partition its space of states into the eigenspaces of the parity transformations in the flavor space, generating the subgroup $Z_2^{\times(N-1)}$. It is proven that the lowest-energy states in these eigenspaces are nondegenerate and assemble in antisymmetric tensors or pseudotensors. At the valence-bond solid point, they constitute the $2^{N-1}$-fold degenerate ground state with fully broken parity-transformation symmetry.

Intertwined order and holography: the case of the parity breaking pair density wave

We present a minimal bottom-up extension of the Chern-Simons bulk action for holographic translational symmetry breaking that naturally gives rise to pair density waves. We construct stationary inhomogeneous black hole solutions in which both the U(1) symmetry and spatially translational symmetry are spontaneously broken at finite temperature and charge density. This novel solution provides a dual description of a superconducting phase intertwined with charge, current and parity orders.

Hall viscosity from effective field theory

For two-dimensional non-dissipative fluids with broken parity, we show via effective field theory methods that the infrared dynamics generically exhibit Hall viscosity--a conservative form of viscosity compatible with two-dimensional isotropy. The equality between the Hall viscosity coefficient and the ground state's intrinsic angular momentum density follows straightforwardly from their descending from the same Lagrangian term of the low-energy effective action. We show that for such fluids sound waves are not purely longitudinal, but acquire an elliptical polarization, with transverse-to-lon…

A lattice mean-field study of the phase diagram of interacting parity-breaking Weyl semimetals

We perform a mean-field study of the phase diagram of interacting Weyl semimetals with broken parity, that is, with different densities of right- and left-handed quasiparticles. As a simple model system, we consider the Wilson-Dirac Hamiltonian with the chiral chemical potential and on-site repulsive interactions. We find that the chiral chemical potential somewhat shrinks the region of the pion condensation (Aoki phase) in the parameter space of the bare mass and the interaction strength, so that the condensation thresholds are at smaller interaction strengths. The renormalized chiral chemica…