The occurrence of nonadiabatic effects in the vibrational properties of metals has been predicted since the 1960s, but hardly confirmed experimentally. We report the first fully ab initio calculations of nonadiabatic frequencies of a number of conventional (hcp Ti and Mg) and layered metals (${\mathrm{MgB}}_2$, ${\mathrm{CaC}}_6$, and other intercalated graphites). Nonadiabatic effects can be spectacularly large (up to 30% of the phonon frequencies) in both cases, but they can only be experimentally observed in the Raman spectra of layered compounds. In layered metals nonadiabatic effects are crucial to explaining the observed Raman shifts and linewidths. Moreover, we show that those quantities can be used to extract the electron momentum-relaxation time.

We compute the electronic structure, momentum resolved spectral function and optical conductivity of the new superconductor ${\mathrm{LaO}}_{1-x}{\mathrm{F}}_x\mathrm{FeAs}$ within the combination of the density functional theory and dynamical mean field theory. We find that the compound in the normal state is a strongly correlated metal and the parent compound is a bad metal at the verge of the metal insulator transition. We argue that the superconductivity is not phonon mediated.

We have succeeded in determining the charge of individual colloidal particles with resolution higher than the elementary charge. The number of elementary charges on a particle is obtained from the analysis of optical tracking data of weakly charged silica spheres in an electric field in a nonpolar medium. The analysis also yields an accurate value of the particle size. Measurement of the charge as a function of time reveals events in which the particle loses or gains an elementary charge due to ionization or recombination processes at the surface.

We search for the standard model Higgs boson produced in association with an electroweak vector boson in events with no identified charged leptons, large imbalance in transverse momentum, and two jets where at least one contains a secondary vertex consistent with the decay of $b$ hadrons. We use $\sim 1{\mathrm{fb}}^{-1}$ integrated luminosity of $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ recorded by the Collider Detector at Fermilab II experiment at the Tevatron. We find 268 (16) single (double) $b$-tagged candidate events, where $248\pm 43$ ($14.4\pm 2.7$) are expected from standard model background processes. We observe no significant excess over the expected background and thus set 95% confidence level upper limits on the Higgs boson production cross section for several Higgs boson masses ranging from 110 to $140\mathrm{GeV}/c^2$. For a mass of $115\mathrm{GeV}/c^2$, the observed (expected) limit is 20.4 (14.2) times the standard model prediction.

We analyze Hawking evaporation of the Callan-Giddings-Harvey-Strominger black holes from a quantum geometry perspective and show that information is not lost, primarily because the quantum space-time is sufficiently larger than the classical. Using suitable approximations to extract physics from quantum space-times we establish that (i) the future null infinity of the quantum space-time is sufficiently long for the past vacuum to evolve to a pure state in the future, (ii) this state has a finite norm in the future Fock space, and (iii) all the information comes out at future infinity; there are no remnants.

We report the first observation of photon antibunching in the photoluminescence from single carbon nanotubes. The emergence of a fast luminescence decay component under strong optical excitation indicates that Auger processes are partially responsible for inhibiting two-photon generation. Additionally, the presence of exciton localization at low temperatures ensures that nanotubes emit photons predominantly one by one. The fact that multiphoton emission probability can be smaller than 5% suggests that carbon nanotubes could be used as a source of single photons for applications in quantum cryptography.

We present the design for an absorbing metamaterial (MM) with near unity absorbance $A(\omega )$. Our structure consists of two MM resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cell layer. We fabricate, characterize, and analyze a MM absorber with a slightly lower predicted $A(\omega )$ of 96%. Unlike conventional absorbers, our MM consists solely of metallic elements. The substrate can therefore be optimized for other parameters of interest. We experimentally demonstrate a peak $A(\omega )$ greater than 88% at 11.5 GHz.

Forming the same heavy compound nucleus with different isotopes of the projectile and target elements allows nuclear structure effects in the entrance channel (resulting in static deformation) and in the dinuclear system to be disentangled. Using three isotopes of Ti and W, forming ${}^{232}\mathrm{Cm}$, with measurement spanning the capture barrier energies, alignment of the heavy prolate deformed nucleus is shown to be the main reason for the broadening of the mass distribution of the quasifission fragments as the beam energy is reduced. The complex, consistently evolving mass-angle correlations that are observed carry more information than the integrated mass or angular distributions, and should severely test models of quasifission.

Sub-10 nm wide graphene nanoribbon field-effect transistors (GNRFETs) are studied systematically. All sub-10 nm GNRs afforded semiconducting FETs without exception, with $I_{\mathrm{on}}/I_{\mathrm{off}}$ ratio up to ${10}^6$ and on-state current density as high as $\sim 2000\mu \mathrm{A}/\mu \mathrm{m}$. We estimated carrier mobility $\sim 200{\mathrm{cm}}^2/\mathrm{V}\mathrm{s}$ and scattering mean free path $\sim 10\mathrm{nm}$ in sub-10 nm GNRs. Scattering mechanisms by edges, acoustic phonon, and defects are discussed. The sub-10 nm GNRFETs are comparable to small diameter ($d\le \sim 1.2\mathrm{nm}$) carbon nanotube FETs with Pd contacts in on-state current density and $I_{\mathrm{on}}/I_{\mathrm{off}}$ ratio, but have the advantage of producing all-semiconducting devices.

We predict squeezed light generation through the spontaneous rotational symmetry breaking occurring in a degenerate optical parametric oscillator (DOPO) pumped above threshold. We show, within the linearized theory, that a DOPO with spherical mirrors, in which the signal and idler fields correspond to first-order Laguerre-Gauss modes, produces a perfectly squeezed vacuum with the shape of a Hermite-Gauss mode. This occurs at any pumping level above threshold; hence, the phenomenon is noncritical. Imperfections of the rotational symmetry, due, e.g., to cavity anisotropy, are shown to have a small impact.

We introduce an equation for protein native topology based on recent analysis of data from the Protein Data Bank and on a generalization of the Landau-Peierls instability criterion for fractals. The equation relates the protein fractal dimension $d_f$, the spectral dimension $d_s$, and the number of amino acids $N$. Deviations from the equation may render a protein unfolded. The fractal nature of proteins is shown to bridge their seemingly conflicting properties of stability and flexibility. Over 500 proteins have been analyzed ($d_f$, $d_s$, and $N$) and found to obey this equation of state.

The blackbody nature of the cosmic microwave background (CMB) radiation spectrum is used in a modern test of the Copernican principle. The reionized universe serves as a mirror to reflect CMB photons, thereby permitting a view of ourselves and the local gravitational potential. By comparing with measurements of the CMB spectrum, a limit is placed on the possibility that we occupy a privileged location, residing at the center of a large void. The Hubble diagram inferred from lines of sight originating at the center of the void may be misinterpreted to indicate cosmic acceleration. Current limits on spectral distortions are shown to exclude the largest voids which mimic cosmic acceleration. More sensitive measurements of the CMB spectrum could prove the existence of such a void or confirm the validity of the Copernican principle.

We investigate theoretically the behavior of the current oscillations in an electronic Mach-Zehnder interferometer (MZI) as a function of its source bias. Recently, the MZI visibility data showed an unexplained lobe pattern with a peculiar phase rigidity. Moreover, the effect did not depend on the MZI path length difference. We argue that these effects may be a new many-body manifestation of particle-wave duality in quantum mechanics. When biasing the interferometer sources so much that multiple electrons are on each arm at any instant in time, quantum shot noise (a particle phenomena) must affect the interference pattern of the electrons that create it. A solution to the interaction Hamiltonian presented here shows that the interference visibility has a lobe pattern with applied bias that has a period proportional to the average path length and independent of the path length difference, together with a phase rigidity.

We study nonequilibrium dephasing in an electronic Mach-Zehnder interferometer. We demonstrate that the shot noise at the beam splitter of the interferometer generates an ensemble of nonequilibrium electron density configurations and that electron interactions induce configuration-specific phase shifts of an interfering electron. The resulting dephasing exhibits two characteristic features, a lobe pattern in the visibility and phase jumps of $\pi$, in good agreement with experimental data.

We report the measurements of the heat capacity of ${}^4\mathrm{He}$ confined in nanoporous Gelsil glass that has nanopores of 2.5-nm diameter at pressures up to 5.3 MPa. The heat capacity has a broad peak at a temperature much higher than the superfluid transition temperature obtained using the torsional oscillator technique. The peak provides definite thermodynamic evidence for the formation of localized Bose-Einstein condensates on nanometer length scales. The temperature dependence of the heat capacity is described well by the excitations of phonons and rotons, supporting the existence of localized Bose-Einstein condensates.

Using a dual-mode STM-AFM microscope operating below 50 mK we measured the local density of states along small normal wires connected at both ends to superconductors with different phases. We observe that a uniform minigap can develop in the whole normal wire and in the superconductors near the interfaces. The minigap depends periodically on the phase difference. The quasiclassical theory of superconductivity applied to a simplified 1D model geometry accounts well for the data.

Solid films of DNA with and without the chemotherapeutic agent cisplatin bonded to guanine were bombarded with electrons of 1, 10, 100, and 60 000 eV causing single and double strand breaks. In the presence of cisplatin this damage was increased by factors varying from 1.3 to 4.4 owing to an increase in bond dissociation triggered by the formation of transient anions. This mechanism may lie at the basis of the efficiency of concomitant cisplatin-radiation therapy.

The generalized two-center cluster model, which can treat static structures and dynamical reactions in excited states, is applied to the light neutron-rich system, ${}^{12}\mathrm{Be}=\alpha +\alpha +4N$. We discuss the change of the neutrons’ configuration around two $\alpha$ cores from the covalent structure to the ionic one. We show that, in the unbound region above particle-decay thresholds, the ionic configurations appear as the molecular resonances of $\alpha +{}^8\mathrm{He}$, ${}^6\mathrm{He}+{}^6\mathrm{He}$, and ${}^5\mathrm{He}+{}^7\mathrm{He}$. A new type of superdeformation is possible, and we find here a covalent superdeformation with a hybrid configuration of both the covalent and ionic structures. The excitation of these exotic structures through the two-neutron transfer reaction is also discussed.

With examples of two parallel dielectric gratings and two arrays of thin parallel dielectric cylinders, it is shown that the interaction between trapped electromagnetic modes can lead to scattering resonances with practically zero width. Such resonances are the bound states in the radiation continuum first discovered in quantum systems by von Neumann and Wigner. Potential applications of such photonic systems include: large amplification of electromagnetic fields within photonic structures and, hence, enhancement of nonlinear phenomena, biosensing, as well as perfect filters and waveguides for a particular frequency, and impurity detection.

In order to express specific genes at the right time, the transcription of genes is regulated by the presence and absence of transcription factor molecules. With transcription factor concentrations undergoing constant changes, gene transcription takes place out of equilibrium. In this Letter we discuss a simple mapping between dynamic models of gene expression and stochastic systems driven out of equilibrium. Using this mapping, results of out-of-equilibrium statistical mechanics such as the Jarzynski equality and the fluctuation theorem are demonstrated for gene expression dynamics. Applications of this approach include the determination of regulatory interactions between genes from experimental gene expression data.