We illustrate that open quantum systems composed of neutral, ultracold atoms in one-dimensional optical lattices can exhibit behavior analogous to semiconductor electronic circuits. A correspondence is demonstrated for bosonic atoms, and the experimental requirements to realize these devices are established. The analysis follows from a derivation of a quantum master equation for this general class of open quantum systems.

We report on residual-gas damping of the motion of a macroscopic test mass enclosed in a nearby housing in the molecular flow regime. The damping coefficient, and thus the associated thermal force noise, is found to increase significantly when the distance between the test mass and surrounding walls is smaller than the test mass itself. The effect has been investigated with two torsion pendulums of different geometry and has been modeled in a numerical simulation whose predictions are in good agreement with the measurements. Relevant to a wide variety of small-force experiments, the residual-gas force noise power for the test masses in the LISA gravitational wave observatory is roughly a factor 15 larger than in an infinite gas volume, though still compatible with the target acceleration noise of $3\mathrm{fm}{\mathrm{s}}^{-2}{\mathrm{Hz}}^{-1/2}$ at the foreseen pressure below ${10}^{-6}\mathrm{Pa}$.

We investigate the dynamical Casimir effect in a coplanar waveguide (CPW) terminated by a superconducting quantum interference device (SQUID). Changing the magnetic flux through the SQUID parametrically modulates the boundary condition of the CPW, and thereby, its effective length. Effective boundary velocities comparable to the speed of light in the CPW result in broadband photon generation which is identical to the one calculated in the dynamical Casimir effect for a single oscillating mirror. We estimate the power of the radiation for realistic parameters and show that it is experimentally feasible to directly detect this nonclassical broadband radiation.

We have identified the cyclotron resonance response of the purest graphene ever investigated, which can be found in nature on the surface of bulk graphite, in the form of decoupled layers from the substrate material. Probing such flakes with Landau level spectroscopy in the THz range at very low magnetic fields, we demonstrate a superior electronic quality of these ultralow density layers ($n_0\approx 3\times {10}^9{\mathrm{cm}}^{-2}$) expressed by the carrier mobility in excess of ${10}^7{\mathrm{cm}}^2/(\mathrm{V}·\mathrm{s})$ or scattering time of $\tau \approx 20\mathrm{ps}$. These parameters set new and surprisingly high limits for intrinsic properties of graphene and represent an important challenge for further developments of current graphene technologies.

Zoom-whirl behavior has the reputation of being a rare phenomenon. The concern has been that gravitational radiation would drain angular momentum so rapidly that generic orbits would circularize before zoom-whirl behavior could play out, and only rare highly tuned orbits would retain their imprint. Using full numerical relativity, we catch zoom-whirl behavior despite dissipation. The larger the mass ratio, the longer the pair can spend in orbit before merging and therefore the more zooms and whirls seen. Larger spins also enhance zoom whirliness. An important implication is that these eccentric orbits can merge during a whirl phase, before enough angular momentum has been lost to truly circularize the orbit. Waveforms will be modulated by the harmonics of zoom-whirls, showing quiet phases during zooms and louder glitches during whirls.

We have achieved Bose-Einstein condensation of ${}^{40}\mathrm{Ca}$, the first for an alkaline earth element. The influence of elastic and inelastic collisions associated with the large ground-state $s$-wave scattering length of ${}^{40}\mathrm{Ca}$ was measured. From these findings, an optimized loading and cooling scheme was developed that allowed us to condense about $2\times {10}^4$ atoms after laser cooling in a two-stage magneto-optical trap and subsequent forced evaporation in a crossed dipole trap within less than 3 s. The condensation of an alkaline earth element opens novel opportunities for precision measurements on the narrow intercombination lines as well as investigations of molecular states at the ${}^{1}S\mathrm{\text{−}}{}^{3}P$ asymptotes.

We present a set of functional equations defining the anomalous dimensions of arbitrary local single trace operators in planar $\mathcal{N}=4$ supersymmetric Yang-Mills theory. It takes the form of a $Y$ system based on the integrability of the dual superstring $\sigma$ model on the five-dimensional anti–de Sitter space (${\mathrm{AdS}}_5\times {\mathrm{S}}^5$) background. This $Y$ system passes some very important tests: it incorporates the full asymptotic Bethe ansatz at large length of operator $L$, including the dressing factor, and it confirms all recently found wrapping corrections. The recently proposed ${\mathrm{AdS}}_4/\mathrm{\text{three-dimensional}}$ conformal field theory duality is also treated in a similar fashion.

We report an angle resolved photoemission spectroscopy study of quantum critical scaling in the single-particle spectral function of a novel anisotropic metal ${\mathrm{Li}}_{0.9}{\mathrm{Mo}}_6{\mathrm{O}}_{17}$. We find a temperature ($T$) scaling exponent value and also low-$T$ angle resolved photoemission spectroscopy line shapes that are very challenging for current one-dimensional theory frameworks. These results add a new spectroscopic component to a growing collection of puzzling low-$T$ transport behaviors of this material.

In the process of spontaneous parametric down-conversion, photons from a pump field are converted to signal and idler photon pairs in a nonlinear crystal. The reversed process, or up-conversion of these pairs back to single photons in a second crystal, is also possible. Here, we present experimental measurements of the up-conversion rate with a controlled time delay introduced between the signal and idler photons. As a function of delay, this rate presents a full width at half maximum of 27.9 fs under our experimental conditions, and we further demonstrate that group delay dispersion of the photon pairs broadens this width. These observations are in close agreement with our calculations, thus demonstrating an ultrafast, nonclassical correlation between the signal and idler waves.

We present a combined theoretical and experimental study of ultrafast wave-packet dynamics in the dissociative ionization of ${\mathrm{H}}_2$ molecules as a result of irradiation with an extreme-ultraviolet (XUV) pulse followed by an infrared (IR) pulse. In experiments where the duration of both the XUV and IR pulses are shorter than the vibrational period of $\mathrm{H}_2{}^{+}$, dephasing and rephasing of the vibrational wave packet that is formed in $\mathrm{H}_2{}^{+}$ upon ionization of the neutral molecule by the XUV pulse is observed. In experiments where the duration of the IR pulse exceeds the vibrational period of $\mathrm{H}_2{}^{+}$ (15 fs), a pronounced dependence of the ${\mathrm{H}}^{+}$ kinetic energy distribution on XUV-IR delay is observed that can be explained in terms of the adiabatic propagation of the $\mathrm{H}_2{}^{+}$ wave packet on field-dressed potential energy curves.

In supernova cores, nuclear “pasta” phases such as a triangular lattice of rodlike nuclei and layered structure of slablike nuclei are considered to exist. However, it is still unclear whether or not they are actually formed in collapsing supernova cores. Using ab initio simulations called quantum molecular dynamics, here we solve this problem by demonstrating that a lattice of rodlike nuclei is formed from a bcc lattice by compression. We also find that, in the transition process, the system undergoes a zigzag configuration of elongated nuclei, which are formed by a fusion of two original spherical nuclei.

Hydrogen molecules in selected core-nonpenetrating Rydberg-Stark states have been decelerated from a mean initial velocity of $500\mathrm{m}/\mathrm{s}$ to zero velocity in the laboratory frame and loaded into a three-dimensional electrostatic trap. Trapping times, measured by pulsed electric field ionization of the trapped molecules, are found to be limited by collisional processes. As Rydberg states can be deexcited to the absolute ground state, the method can be applied to generate cold samples of a wide range of species.

The thermal switching behavior of individual in-plane magnetized $\mathrm{Fe}/\mathrm{W}(110)$ nanoislands is investigated by a combined study of variable-temperature spin-polarized scanning tunneling microscopy and Monte Carlo simulations. Even for islands consisting of less than 100 atoms the magnetization reversal takes place via nucleation and propagation. The Arrhenius prefactor is found to strongly depend on the individual island size and shape, and based on the experimental results a simple model is developed to describe the magnetization reversal in terms of metastable states. Complementary Monte Carlo simulations confirm the model and provide new insight into the microscopic processes involved in magnetization reversal of smallest nanomagnets.

The passage of a free-electron beam through a nanohole in a periodically layered metal-dielectric structure creates a new type of tunable, nanoscale radiation source—a “light well”. In the reported demonstration, tunable light is generated at an intensity of $\sim 200\mathrm{W}/{\mathrm{cm}}^2$ as electrons with energies in the 20–40 keV range are injected into gold-silica well structures with a lateral size of just a few hundred nanometers.

We show theoretically that a large Bell inequality violation can be obtained with human eyes as detectors, in a “micro-macro” experiment where one photon from an entangled pair is greatly amplified via stimulated emission. The violation is robust under photon loss. This leads to an apparent paradox, which we resolve by noting that the violation proves the existence of entanglement before the amplification. The same is true for the micro-macro experiments performed so far with conventional detectors. However, we also prove that there is genuine micro-macro entanglement even for high loss.

We report the influence of the field effect on the dc resistance and Hall coefficient in the strain-induced Mott insulating state of an organic superconductor $\kappa \mathrm{\text{−}}(\mathrm{BEDT}\mathrm{\text{−}}\mathrm{TTF}{)}_2\mathrm{Cu}[\mathrm{N}(\mathrm{CN}{)}_2]\mathrm{Br}$. Conductivity obeys the formula for an activated transport ${\sigma }_{\square }={\sigma }_0\exp (-W/k_{B}T)$, where ${\sigma }_0$ is a constant and $W$ depends on the gate voltage. The gate-voltage dependence of the Hall coefficient shows that, unlike in conventional field-effect transistors, the effective mobility of dense hole carriers ($\sim 1.6\times {10}^{14}{\mathrm{cm}}^{-2}$) is enhanced by a positive gate voltage. This implies that carrier doping involves delocalization of intrinsic carriers that were initially localized due to electron correlation.

Using time-resolved single-shot pump-probe microscopy we unveil the mechanism and the time scale of all-optical magnetization reversal by a single circularly polarized 100 fs laser pulse. We demonstrate that the reversal has a linear character, i.e., does not involve precession but occurs via a strongly nonequilibrium state. Calculations show that the reversal time which can be achieved via this mechanism is within 10 ps for a 30 nm domain. Using two single subpicosecond laser pulses we demonstrate that for a $5\mu \mathrm{m}$ domain the magnetic information can be recorded and readout within 30 ps, which is the fastest “write-read” event demonstrated for magnetic recording so far.

Traumatic brain injury (TBI) has become a signature injury of current military conflicts, with debilitating, costly, and long-lasting effects. Although mechanisms by which head impacts cause TBI have been well researched, the mechanisms by which blasts cause TBI are not understood. From numerical hydrodynamic simulations, we have discovered that nonlethal blasts can induce sufficient skull flexure to generate potentially damaging loads in the brain, even without a head impact. The possibility that this mechanism may contribute to TBI has implications for injury diagnosis and armor design.

We numerically demonstrate a simple one-dimensional model of an acoustic diode formed by coupling a superlattice with a strongly nonlinear medium. The first numerical observation is presented of a significant rectifying effect on the acoustic energy flux within particular ranges of frequencies. By studying the underlying rectifying mechanism and the parameter dependence of the rectifying efficiency, the effectiveness of the acoustic diode is proved despite its simplicity. We also briefly discuss possible schemes of the experimental realization of this model as well as devising more efficient models.

We argue that theories of the strong electroweak symmetry breaking sector necessarily contain new spin 0 states at the TeV scale in the $\overline{t}t$ and $\overline{t}b/\overline{b}t$ channels, even if the third generation quarks are not composite at the TeV scale. These states couple sufficiently strongly to third generation quarks to have significant production at LHC via $gg\to {\phi }^0$ or $gb\to t{\phi }^{-}$. The existence of narrow resonances in QCD suggests that the strong electroweak breaking sector contains narrow resonances that decay to $\overline{t}t$ or $\overline{t}b/\overline{b}t$, with potentially significant branching fractions to 3 or more longitudinal $W$ and $Z$ bosons. These may give new “smoking gun” signals of strong electroweak symmetry breaking.