Observation of non-Abelian statistics for the $e/4$ quasiparticles in the $\nu =\frac{5}{2}$ fractional quantum Hall state remains an outstanding experimental problem. The non-Abelian statistics are linked to the presence of additional low energy states in a system with localized quasiparticles, and, hence, an additional low temperature entropy. Recent experiments, which detect changes in the number of quasiparticles trapped in a local potential well as a function of an applied gate voltage, $V_G$, provide a possibility for measuring this entropy, if carried out over a suitable range of temperatures, $T$. We present a microscopic model for quasiparticles in a potential well and study the effects of non-Abelian statistics on the charge stability diagram in the $V_G-T$ plane, including broadening at finite temperature. We predict a measurable slope for the first quasiparticle charging line and an even-odd effect in the diagram, which is a signature of non-Abelian statistics.

In order to examine to what extent the rigid-band-like electron doping scenario is applicable to the transition metal-substituted Fe-based superconductors, we have performed angle-resolved photoemission spectroscopy studies of $\mathrm{Ba}({\mathrm{Fe}}_{1-x}{\mathrm{Ni}}_x{)}_2{\mathrm{As}}_2$ (Ni-122) and $\mathrm{Ba}({\mathrm{Fe}}_{1-x}{\mathrm{Cu}}_x{)}_2{\mathrm{As}}_2$ (Cu-122), and compared the results with $\mathrm{Ba}({\mathrm{Fe}}_{1-x}{\mathrm{Co}}_x{)}_2{\mathrm{As}}_2$ (Co-122). We find that Ni $3d$-derived features are formed below the Fe $3d$ band and that Cu $3d$-derived ones further below it. The electron and hole Fermi surface (FS) volumes are found to increase and decrease with substitution, respectively, qualitatively consistent with the rigid-band model. However, the total extra electron number estimated from the FS volumes (the total electron FS volume minus the total hole FS volume) is found to decrease in going from Co-, Ni-, to Cu-122 for a fixed nominal extra electron number, that is, the number of electrons that participate in the formation of FS decreases with increasing impurity potential. We find that the Néel temperature $T_N$ and the critical temperature $T_c$ maximum are determined by the FS volumes rather than the nominal extra electron concentration or the substituted atom concentration.

Strain engineering of functional properties in epitaxial thin films of strongly correlated oxides exhibiting octahedral-framework structures is hindered by the lack of adequate misfit relaxation models. Here we present unreported experimental evidence of a four-stage hierarchical development of octahedral-framework perturbations resulting from a progressive imbalance between electronic, elastic, and octahedral tilting energies in ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_3$ epitaxial thin films grown on ${\mathrm{SrTiO}}_3$ substrates. Electronic softening of the Mn-O bonds near the substrate leads to the formation of an interfacial layer clamped to the substrate with strongly degraded magnetotransport properties, i.e., the so-called dead layer, while rigid octahedral tilts become relevant at advanced growth stages without significant effects on charge transport and magnetic ordering.

We study the crossover between thermodynamic Casimir forces arising from long-range fluctuations due to Goldstone modes and those arising from critical fluctuations. Both types of forces exist in the low-temperature phase of $\mathrm{O}(n)$-symmetric systems for $n>1$ in a $d$-dimensional $L_{\parallel }^{d-1}\times L$ slab geometry with a finite aspect ratio $\rho =L/L_{\parallel }$. Our finite-size renormalization-group treatment for periodic boundary conditions describes the entire crossover from the Goldstone regime with a nonvanishing constant tail of the finite-size scaling function far below $T_c$ up to the region far above $T_c$ including the critical regime with a minimum of the scaling function slightly below $T_c$. Our analytic result for $\rho \ll 1$ agrees well with Monte Carlo data for the three-dimensional $XY$ model. A quantitative prediction is given for the crossover of systems in the Heisenberg universality class.

We present nonlinear dielectric measurements of glass-forming glycerol and propylene carbonate applying electrical fields up to $671\mathrm{kV}/\mathrm{cm}$. The measurements extend to sufficiently high frequencies to allow for the investigation of the nonlinear behavior in the regime of the so-far mysterious excess wing, showing up in the loss spectra of many glass formers as a second power law at high frequencies. Surprisingly, we find a complete lack of nonlinear behavior in the excess wing, in marked contrast to the $\alpha$ relaxation where, in agreement with previous reports, a strong increase of dielectric constant and loss is found.

Numerically predicting rate constants of protein folding and other relevant biological events is still a significant challenge. We show that the combination of partial path transition interface sampling with the optimal interfaces and free-energy profiles provided by path collective variables makes the rate calculation for practical biological applications feasible and efficient. This methodology can reproduce the experimental rate constant of Trp-cage miniprotein folding with the same level of accuracy as transition path sampling at a fraction of the cost.

We study thermalization in a one-dimensional quantum system consisting of a noninteracting fermionic chain with each site of the chain coupled to an additional bath site. Using a density matrix renormalization group algorithm we investigate the time evolution of the observables in the chain after a quantum quench. For low densities we show that the intermediate time dynamics can be quantitatively described by a system of coupled equations of motion. For higher densities our numerical results show a prethermalization for the local observables at intermediate times and a full thermalization to the grand canonical ensemble at long times. For the case of a weak bath-chain coupling we find, in particular, a Fermi momentum distribution in the chain in equilibrium in spite of the seemingly oversimplified bath in our model.

We study the head-on collision of fluid particles well within the kinetic energy dominated regime ($\gamma =8$ to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The gravitational radiation reaches luminosities of $0.014c^5/G$, carrying $16\pm 2\%$ of the total energy.

We experimentally studied the three-body fragmentation dynamics of ${\mathrm{CO}}_2$ initiated by intense femtosecond laser pulses. Sequential and nonsequential fragmentations were precisely separated and identified for $\mathrm{CO}_2{}^{3+}$ to break up into ${\mathrm{O}}^{+}+{\mathrm{C}}^{+}+{\mathrm{O}}^{+}$ ions. With accurate measurements of three-dimensional momentum vectors of the correlated atomic ions and calculations of the high-level ab initio potential of $\mathrm{CO}_2{}^{3+}$, we reconstructed the geometric structure of $\mathrm{CO}_2{}^{3+}$ before fragmentation, which turns out to be very close to that of the neutral ${\mathrm{CO}}_2$ molecule before laser irradiation. Our study indicated that Coulomb explosion is a promising approach for imaging geometric structures of polyatomic molecules if the fragmentation dynamics can be clearly clarified and the appropriate dissociation potential is provided for multiply charged molecular ions.

We consider theoretically the spaser that is excited electrically via a nanowire with ballistic quantum conductance. We show that, in the extreme quantum regime, i.e., for a single conductance-quantum nanowire, the spaser with a core made of common plasmonic metals, such as silver and gold, is fundamentally possible. For ballistic nanowires with multiple-quanta or nonquantized conductance, the performance of the spaser is enhanced in comparison with the extreme quantum limit. The electrically pumped spaser is promising as an optical source, nanoamplifier, and digital logic device for optoelectronic information processing with a speed of $\sim 100\mathrm{GHz}$ to $\sim 100\mathrm{THz}$.

We demonstrate here that the current-driven domain wall (DW) in two dimensions forms a “facet” roughness, distinctive to the conventional self-affine roughness induced by a magnetic field. Despite the different universality classes of these roughnesses, both the current- and field-driven DW speed follow the same creep law only with opposite angular dependences. Such angular dependences result in a stable facet angle, from which a single DW image can unambiguously quantify the spin-transfer torque efficiency, an essential parameter in DW-mediated nanodevices.

We investigate the two-dimensional highly spin-polarized electron accumulation layers commonly appearing near the surface of $n$-type polar semiconductors $\mathrm{BiTe}X$ ($X=\mathrm{I}$, Br, and Cl) by angular-resolved photoemission spectroscopy. Because of the polarity and the strong spin-orbit interaction built in the bulk atomic configurations, the quantized conduction-band subbands show giant Rashba-type spin splitting. The characteristic 2D confinement effect is clearly observed also in the valence bands down to the binding energy of 4 eV. The $X$-dependent Rashba spin-orbit coupling is directly estimated from the observed spin-split subbands, which roughly scales with the inverse of the band-gap size in $\mathrm{BiTe}X$.

We demonstrate the feasibility of element-specific probing of ultrafast spin dynamics in the multisublattice magnet TbFe in the visible spectral range. In particular, we show that one can selectively study the dynamics of Tb and Fe sublattices choosing the wavelength of light below and above 610 nm, respectively. We observe that, despite their antiferromagnetic coupling in the ground state, the Tb and Fe spins temporarily align ferromagnetically after excitation with an intense 55-fs laser pulse, after which they relax to their initial states due to the strong anisotropy in Tb.

Concentrated solutions of ultrashort duplex-forming DNA oligomers may develop various forms of liquid crystal ordering among which is the chiral nematic phase, characterized by a macroscopic helical precession of molecular orientation. The specifics of how chirality propagates from the molecular to the mesoscale is still unclear, both in general and in the case of DNA-based liquid crystals. We have here investigated the onset of nematic ordering and its chiral character in mixtures of natural $D$-DNA oligomers forming right-handed duplex helices and of mirror symmetric ($L$-DNA) molecules, forming left-handed helices. Since the nematic ordering of DNA duplexes is mediated by their end-to-end aggregation into linear columns, by controlling the terminals of both enantiomers we could study the propagation of chirality in solutions where the $D$ and $L$ species form mixtures of homochiral columns, and in solutions of heterochiral columns. The two systems behave in markedly different fashion. By adopting a simple model based on nearest-neighbor interactions, we account for the different observed dependence of the chirality of these two systems on the enantiomeric ratio.

We study to what extent cortical columns with their particular wiring boost neural computation. Upon a vast survey of columnar networks performing various real-world cognitive tasks, we detect no signs of enhancement. It is on a mesoscopic—intercolumnar—scale that the existence of columns, largely irrespective of their inner organization, enhances the speed of information transfer and minimizes the total wiring length required to bind distributed columnar computations towards spatiotemporally coherent results. We suggest that brain efficiency may be related to a doubly fractal connectivity law, resulting in networks with efficiency properties beyond those by scale-free networks.

One fascinating way of revealing quantum nonlocality is the all-versus-nothing test due to Greenberger, Horne, and Zeilinger (GHZ) known as the GHZ paradox. So far genuine multipartite and multilevel GHZ paradoxes are known to exist only in systems containing an odd number of particles. Here we shall construct GHZ paradoxes for an arbitrary number (greater than 3) of particles with the help of qudit graph states on a special kind of graphs, called GHZ graphs. Furthermore, based on the GHZ paradox arising from a GHZ graph, we derive a Bell inequality with two $d$-outcome observables for each observer, whose maximal violation attained by the corresponding graph state, and a Kochen-Specker inequality testing the quantum contextuality in a state-independent fashion.

The nonequilibrium dynamics of a small quantum system coupled to a dissipative environment is studied. We show that (i) the oscillatory dynamics close to a coherent-to-incoherent transition is significantly different from the one of the classical damped harmonic oscillator and that (ii) non-Markovian memory plays a prominent role in the time evolution after a quantum quench.

We demonstrate that any scaling source in the radiation era produces a background of gravitational waves with an exact scale-invariant power spectrum. Cosmic defects, created after a phase transition in the early universe, are such a scaling source. We emphasize that the result is independent of the topology of the cosmic defects, the order of phase transition, and the nature of the symmetry broken, global or gauged. As an example, using large-scale numerical simulations, we calculate the scale-invariant gravitational wave power spectrum generated by the dynamics of a global $\mathrm{O}(N)$ scalar theory. The result approaches the large $N$ theoretical prediction as $N^{-2}$, albeit with a large coefficient. The signal from global cosmic strings is $\mathcal{O}(100)$ times larger than the large $N$ prediction.

We use the AdS/CFT conjecture to investigate the thermalization of large-$N_c$ $\mathcal{N}=4$ super Yang-Mills plasma in the limit of large but finite ’t Hooft coupling. On the gravity side, we supplement the type IIB supergravity action by the full set of $\mathcal{O}({\alpha }^{\prime 3})$ operators, which enables us to derive $\mathcal{O}({\lambda }^{-3/2})$ corrections to the emission spectrum of prompt photons in one model of holographic thermalization. Decreasing the coupling strength from the $\lambda =\infty$ limit, we observe a qualitative change in the way the photon spectral density approaches its thermal limit as a function of the photon energy. We interpret this behavior as a sign of the thermalization pattern of the plasma shifting from top-down towards bottom-up.

We demonstrate that the quantum-mechanical description of Rutherford scattering has a photonic counterpart in a new form of single particle photothermal microscopy. Using a split detector we provide experimental evidence that photons are deflected by a photothermal potential that is created by a local refractive index change around a heated nanoparticle. The deflection experienced is shown to be the analog to the deflection of a massive particle wave packet in unscreened spinless Coulomb scattering. The experimentally found focal detection geometry reveals a lateral split feature which will allow new correlation-based velocimetry experiments of absorbing particles with ultrahigh sensitivity.