Entanglement entropy of (3+1)D topological orders with excitations

Excitations in (3+1)D topologically ordered phases have very rich structures. (3+1)D topological phases support both point-like and string-like excitations, and in particular the loop (closed string) excitations may admit knotted and linked structures. In this work, we ask the question how different types of topological excitations contribute to the entanglement entropy, or alternatively, can we use the entanglement entropy to detect the structure of excitations, and further obtain the information of the underlying topological orders? We are mainly interested in (3+1)D topological orders that can be realized in Dijkgraaf-Witten gauge theories, which are labeled by a finite group $G$ and its group 4-cocycle $\omega\in\mathcal{H}^4[G;U(1)]$ up to group automorphisms. We find that each topological excitation contributes a universal constant $\ln d_i$ to the entanglement entropy, where $d_i$ is the quantum dimension that depends on both the structure of the excitation and the data $(G,\,\omega)$. The entanglement entropy of the excitations of the linked/unlinked topology can capture different information of the DW theory $(G,\,\omega)$. In particular, the entanglement entropy introduced by Hopf-link loop excitations can distinguish certain group 4-cocycles $\omega$ from the others.Comment: 12 pages, 4 figures; v2: minor changes, published versio

Finite volume effects of the Nambu-Jona-Lasinio model with the running coupling constant

With the Schwinger's proper-time formalism of the Nambu-Jona-Lasinio model, we investigate the finite volume effects in the presence of magnetic fields. Since the coupling constant $G$ can be influenced by strong magnetic fields, the model is solved with a running coupling constant $G(B)$ which is fitted by the lattice average $(\Sigma_u+\Sigma_d)/2$ and difference $\Sigma_u-\Sigma_d$. The investigation mainly focuses on the constituent quark mass and the thermal susceptibility depending on the magnetic fields, the temperatures and the finite sizes. For the model in finite or infinite volume, the magnetic fields can increase the constituent quark mass while the temperatures can decrease it inversely. There is a narrow range of the box length that makes the effects of finite volume perform prominently. The model will behave close to infinite volume limit for larger box length. It is shown that the influence of finite volume can be changed by magnetic fields and temperatures. Finally, we discuss the thermal susceptibility depending on the temperature in finite volume in the presence of magnetic fields.Comment: 13 pages, 6 figure

Charge-dependent transverse momentum and its impact on the search for the chiral magnetic wave

The chiral magnetic wave (CMW) is sought using the charge asymmetry ($A_{\rm ch}$) dependence of anisotropic flow in heavy-ion collisions. The charge dependent transverse momentum ($p_{\rm T}$), however, could play a role as a background. With the string fragmentation models, including PYTHIA, we demonstrate the origin of the $A_{\rm ch}-p_{\rm T}$ correlation and its connection with the local charge conservation (LCC). The impact of $A_{\rm ch}-p_{\rm T}$ and its behavior in varied kinematic windows are also discussed. This study provides more insights for the search for the CMW and comprehending the collective motion of the quark-gluon plasma.Comment: 6 pages, 6 figure

U(1) × U(1) symmetry-protected topological order in Gutzwiller wave functions

Gutzwiller projection is a way to construct many-body wave functions that could carry topological order or symmetry-protected topological (SPT) order. However, an important issue is to determine whether or not a given Gutzwiller-projected wave function (GWF) carries a nontrivial SPT order, and which SPT order is carried by the wave function. In this paper, we numerically study the SPT order in a spin S = 1 GWF on the kagome lattice. Using the standard Monte Carlo method, we directly confirm that the GWF has (1) gapped bulk with short-range correlations, (2) a trivial topological order via a nondegenerate ground state, and zero topological entanglement entropy, (3) a nontrivial U(1) × U(1) SPT order via the Hall conductances of the protecting U(1) × U(1) symmetry, and (4) a symmetry-protected gapless boundary. This represents numerical evidence of continuous symmetry-protected topological order in two-dimensional bosonic lattice systems.Perimeter Institute for Theoretical PhysicsNational Science Foundation (U.S.) (Grant DMR-1005541)National Natural Science Foundation (China) (Grant 11274192)Templeton Foundation (Grant 39901

Mutual Composite Fermion and composite Boson approaches to balanced and imbalanced bilayer quantum Hall system: an electronic analogy of the Helium 4 system

We use both Mutual Composite Fermion (MCF) and Composite Boson (CB) approach to study balanced and im-balanced Bi-Layer Quantum Hall systems (BLQH) and make critical comparisons between the two approaches. We find the CB approach is superior to the MCF approach in studying ground states with different kinds of broken symmetries. In the phase representation of the CB theory, we first study the Excitonic superfluid state (ESF). The theory puts spin and charge degree freedoms in the same footing, explicitly bring out the spin-charge connection and classify all the possible excitations in a systematic way. Then in the dual density representation of the CB theory, we study possible intermediate phases as the distance increases. We propose there are two critical distances $d_{c1} < d_{c2}$ and three phases as the distance increases. When $0 < d < d_{c1}$, the system is in the ESF state which breaks the internal $U(1)$ symmetry, when $d_{c1} < d < d_{c2}$, the system is in an Pseudo-spin density wave (PSDW) state which breaks the translational symmetry, there is a first order transition at $d_{c1}$ driven by the collapsing of magneto-roton minimum at a finite wavevector in the pseudo-spin channel. When $d_{c2} < d < \infty$, the system becomes two weakly coupled $\nu =1/2$ Composite Fermion Fermi Liquid (FL) state. There is also a first order transition at $d= d_{c2}$. We construct a quantum Ginzburg Landau action to describe the transition from ESF to PSDW which break the two completely different symmetries. By using the QGL action, we explicitly show that the PSDW takes a square lattice and analyze in detail the properties of the PSDW at zero and finite temperature.Comment: 29 PRB pages, 18 figures, 2 tables, REVTEX

DopplerBAS: Binaural Audio Synthesis Addressing Doppler Effect

Recently, binaural audio synthesis (BAS) has emerged as a promising research field for its applications in augmented and virtual realities. Binaural audio helps users orient themselves and establish immersion by providing the brain with interaural time differences reflecting spatial information. However, existing BAS methods are limited in terms of phase estimation, which is crucial for spatial hearing. In this paper, we propose the \textbf{DopplerBAS} method to explicitly address the Doppler effect of the moving sound source. Specifically, we calculate the radial relative velocity of the moving speaker in spherical coordinates, which further guides the synthesis of binaural audio. This simple method introduces no additional hyper-parameters and does not modify the loss functions, and is plug-and-play: it scales well to different types of backbones. DopperBAS distinctly improves the representative WarpNet and BinauralGrad backbones in the phase error metric and reaches a new state of the art (SOTA): 0.780 (versus the current SOTA 0.807). Experiments and ablation studies demonstrate the effectiveness of our method.Comment: Accepted to ACL 2023 short paper; key words: binaural audio, stereophonic soun