Impurity-Induced Anomalous Thermal Hall Effect in Chiral SuperconductorsNgampruetikorn, Vudtiwat;Sauls, J. A.
doi: 10.1103/PhysRevLett.124.157002pmid: 32357039
Abstract: Chiral superconductors exhibit novel transport properties that depend on the topology of the order parameter, topology of the Fermi surface, the spectrum of bulk and edge Fermionic excitations, and the structure of the impurity potential. In the case of electronic heat transport, impurities induce an anomalous (zero-field) thermal Hall conductivity that is easily orders of magnitude larger than the quantized edge contribution. The effect originates from branch-conversion scattering of Bogoliubov quasiparticles by the chiral order parameter, induced by potential scattering. The former transfers angular momentum between the condensate and the excitations that transport heat. The anomalous thermal Hall conductivity is shown to depend to the structure of the electron-impurity potential, as well as the winding number, $\nu$, of the chiral order parameter, $\Delta(p)=|\Delta(p)|\,e^{i\nu\phi_{p}}$. The results provide quantitative formulae for interpreting heat transport experiments seeking to identify broken T and P symmetries, as well as the topology of the order parameter for chiral superconductors.
Chiral active hexatics: Giant number fluctuations, waves and destruction of orderMaitra, Ananyo;Lenz, Martin;Voituriez, Raphael
doi: 10.1103/PhysRevLett.125.238005pmid: 33337208
Abstract: Active materials, composed of internally driven particles, have properties that are qualitatively distinct from matter at thermal equilibrium. However, the most spectacular departures from equilibrium phase behaviour are thought to be confined to systems with polar or nematic asymmetry. In this paper, we show that such departures are also displayed in more symmetric phases such as hexatics if, in addition, the constituent particles have chiral asymmetry. We show that chiral active hexatics whose rotation rate does not depend on density have giant number fluctuations. If the rotation rate depends on density, the giant number fluctuations are suppressed due to a novel orientation-density sound mode with a linear dispersion which propagates even in the overdamped limit. However, we demonstrate that beyond a finite but large lengthscale, a chirality and activity-induced relevant nonlinearity invalidates the predictions of the linear theory and destroys the hexatic order. In addition, we show that activity modifies the interactions between defects in the active chiral hexatic phase, making them non-mutual. Finally, to demonstrate the generality of a chiral active hexatic phase we show that it results from the melting of chiral active crystals in finite systems.
Prediction of an Extended Ferroelectric ClathrateZhu, Li;Strobel, Timothy A.;Cohen, R. E.
doi: 10.1103/PhysRevLett.125.127601pmid: 33016718
Abstract: Using first-principles calculations, we predict a lightweight room-temperature ferroelectric carbon-boron framework in a host/guest clathrate structure. This ferroelectric clathrate, with composition ScB$_3$C$_3$, exhibits high polarization density and low mass density compared with widely used commercial ferroelectrics. Molecular dynamics simulations show spontaneous polarization with a moderate above-room-temperature T$_c$ of $\sim$370 K, which implies large susceptibility and possibly large electrocaloric and piezoelectric constants at room temperature. Our findings open the possibility for a new class of ferroelectric materials with potential across a broad range of applications.
How moving cracks in brittle solids choose their pathRozen-Levy, Lital;Kolinski, John M.;Cohen, Gil;Fineberg, Jay
doi: 10.1103/PhysRevLett.125.175501pmid: 33156638
Abstract: While we fundamentally understand the dynamics of 'simple' cracks propagating in brittle solids within perfect (homogeneous) materials, we do not understand how paths of moving cracks are determined. We experimentally study strongly perturbed cracks that propagate between 10-95\% of their limiting velocity within a brittle material. These cracks are deflected by either interaction with sparsely implanted defects or via an intrinsic oscillatory instability in defect-free media. Dense, high-speed measurements of the strain fields surrounding the crack tips reveal that crack paths are governed by the direction of maximal strain energy density. This fundamentally important result may be utilized to either direct or guide running cracks.
Equation of state constraints from the threshold binary mass for prompt collapse of neutron star mergersBauswein, Andreas;Blacker, Sebastian;Vijayan, Vimal;Stergioulas, Nikolaos;Chatziioannou, Katerina;Clark, James A.;Bastian, Niels-Uwe F.;Blaschke, David B.;Cierniak, Mateusz;Fischer, Tobias
doi: 10.1103/PhysRevLett.125.141103pmid: 33064526
Abstract: Using hydrodynamical simulations for a large set of high-density matter equations of state (EoSs) we systematically determine the threshold mass M_thres for prompt black-hole formation in equal-mass and asymmetric neutron star (NS) mergers. We devise the so far most direct, general and accurate method to determine the unknown maximum mass of nonrotating NSs from merger observations revealing M_thres. Considering hybrid EoSs with hadron-quark phase transition, we identify a new, observable signature of quark matter in NS mergers. Furthermore, our findings have direct applications in gravitational wave searches, kilonova interpretations and multi-messenger constraints on NS properties.
Experimental Realization of Near-Field Photonic Routing with All-Electric MetasourcesLong, Yang;Ren, Jie;Guo, Zhiwei;Jiang, Haitao;Wang, Yuqian;Sun, Yong;Chen, Hong
doi: 10.1103/PhysRevLett.125.157401pmid: 33095606
Abstract: The spatially confined evanescent microwave photonics have been proved to be highly desirable in broad practical scenarios ranging from robust information communications to efficient quantum interactions. However, the feasible applications of these photonics modes are limited due to the lack of fundamental understandings and feasible directional coupling approaches at sub-wavelengths. Here, we experimentally demonstrate the efficient near-field photonic routing achieved in waveguides composed of two kinds of single-negative metamaterials. Without mimicking the polarization features, we propose all-electric near-field metasource in subwavelength scale and exemplify its near-field functions like Janus, Huygens and spin sources, corresponding to time-reversal, parity-time and parity symmetries of its inner degree of freedom. Our work furthers the understandings about optical near-field symmetry and feasible engineering approaches of directional couplings, which would pave the way for promising integrated mircrowave photonics devices.
Evidence for Nonlinear Isotope Shift in Yb$^+$ Search for New BosonCounts, Ian;Hur, Joonseok;Craik, Diana P. L. Aude;Jeon, Honggi;Leung, Calvin;Berengut, Julian;Geddes, Amy;Kawasaki, Akio;Jhe, Wonho;Vuletić, Vladan
doi: 10.1103/PhysRevLett.125.123002pmid: 33016768
Abstract: We measure isotope shifts for five Yb$^+$ isotopes with zero nuclear spin on two narrow optical quadrupole transitions ${}^2S_{1/2} \rightarrow {}^2D_{3/2}$, ${}^2S_{1/2} \rightarrow {}^2D_{5/2}$ with an accuracy of $\sim 300$ Hz. The corresponding King plot shows a $3 \times 10^{-7}$ deviation from linearity at the 3 $\sigma$ uncertainty level. Such a nonlinearity can indicate physics beyond the Standard Model (SM) in the form of a new bosonic force carrier, or arise from higher-order nuclear effects within the SM. We identify the quadratic field shift as a possible contributor to the nonlinearity at the observed scale, and show how the nonlinearity pattern can be used in future, more accurate measurements to separate a new-boson signal from nuclear effects.
Revealing the Atomic Site-Dependent g Factor within a Single Magnetic Molecule via the Extended Kondo EffectLiu, Liwei;Yang, Kai;Jiang, Yuhang;Song, Boqun;Xiao, Wende;Song, Shiru;Du, Shixuan;Ouyang, Min;Hofer, Werner A.;Neto, Antonio H. Castro;Gao, Hong-Jun
doi: 10.1103/PhysRevLett.114.126601pmid: 25860762
Abstract: The site-dependent g factor of a single magnetic molecule, with intramolecular resolution, is demonstrated for the first time by low-temperature, high-magnetic-field scanning tunneling microscopy of dehydrogenated Mn-phthalocyanine molecules on Au(111). This is achieved by exploring the magneticfield dependence of the extended Kondo effect at different atomic sites of the molecule. Importantly, an inhomogeneous distribution of the g factor inside a single molecule is revealed. Our results open up a new route to access local spin properties within a single molecule.
Relieving the Hubble tension with primordial magnetic fieldsJedamzik, Karsten;Pogosian, Levon
doi: 10.1103/PhysRevLett.125.181302pmid: 33196251
Abstract: The standard cosmological model determined from the accurate cosmic microwave background measurements made by the Planck satellite implies a value of the Hubble constant $H_0$ that is $4.2$ standard deviations lower than the one determined from Type Ia supernovae. The Planck best fit model also predicts higher values of the matter density fraction $\Omega_m$ and clustering amplitude $S_8$ compared to those obtained from the Dark Energy Survey Year 1 data. Here we show that accounting for the enhanced recombination rate due to additional small-scale inhomogeneities in the baryon density may solve both the $H_0$ and the $S_8-\Omega_m$ tensions. The additional baryon inhomogeneities can be induced by primordial magnetic fields present in the plasma prior to recombination. The required field strength to solve the Hubble tension is just what is needed to explain the existence of galactic, cluster, and extragalactic magnetic fields without relying on dynamo amplification. Our results show clear evidence for this effect and motivate further detailed studies of primordial magnetic fields, setting several well-defined targets for future observations.