We determine the Galactic production rate of strangelets as a canonical input to calculations of the measurable cosmic ray flux of strangelets by performing simulations of strange star mergers and combining the results with recent estimates of stellar binary populations. We find that the flux depends sensitively on the bag constant of the MIT bag model of QCD and disappears for high values of the bag constant and thus more compact strange stars. In the latter case, strange stars could coexist with ordinary neutron stars as they are not converted by the capture of cosmic ray strangelets. An unambiguous detection of an ordinary neutron star would then not rule out the strange matter hypothesis.

Time-resolved valence band photoelectron spectroscopy with a temporal resolution of 135 fs is used to map the entire occupied valence electronic structure of photoexcited gas-phase ${\mathrm{Br}}_2$ molecules during dissociation. The observed shifting and mixing of valence energy levels defines a transition period where the system appears to be intermediate between atoms and molecules. The surprisingly short bond breaking or dissociation time is determined by monitoring in real time how the photoelectron multiplet structure of the free atom arises from the valence states of the photoexcited molecule.

Controllable point junctions between different quantum Hall phases are a necessary building block for the development of mesoscopic circuits based on fractionally charged quasiparticles. We demonstrate how particle-hole duality can be exploited to realize such point-contact junctions. We show an implementation for the case of two quantum Hall liquids at filling factors $\nu =1$ and ${\nu }^{*}\le 1$ in which both the fractional filling ${\nu }^{*}$ and the coupling strength can be finely and independently tuned. A peculiar crossover from insulating to conducting behavior as ${\nu }^{*}$ goes from $1/3$ to 1 is observed. These results highlight the key role played on interedge tunneling by local charge depletion at the point contact.

The fundamental lower bounds on the thermodynamic energy cost of measurement and information erasure are determined. The lower bound on the erasure validates Landauer’s principle for a symmetric memory; for other cases, the bound indicates the breakdown of the principle. Our results constitute the second law of “information thermodynamics,” in which information content and thermodynamic variables are treated on an equal footing.

During thunderstorms on 20 September 2008, a simultaneous detection of $\gamma$ rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 sec, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung $\gamma$ rays arriving from a source which is 60–130 m in distance at 90% confidence level. The observed electrons are likely to be dominated by a primary population escaping from an acceleration region in the clouds.

Fundamental selectivity limits of quantum control are pushed by introducing laser driven optimal dynamic discrimination to create distinguishing excitations on two nearly identical flavin molecules. Even with modest spectral resources, significant specificity is achieved with optimal pulse shapes, which amplify small molecular differences to create distinct, identifying signals. Rather than being a hindrance, system complexity appears to aid the control process and augments control field capability, which bodes well for implementation of quantum control in a variety of demanding applications.

I propose a quantum imaging method that can beat the Rayleigh-Abbe diffraction limit and achieve de Broglie resolution without requiring a multiphoton absorber or coincidence detection. Using the same nonclassical states of light as those for quantum lithography, the proposed method requires only optical intensity measurements, followed by image postprocessing, to produce the same complex quantum interference patterns as those in quantum lithography. The method is expected to be experimentally realizable using current technology.

We propose to use transformation optics to generate a general illusion such that an arbitrary object appears to be like some other object of our choice. This is achieved by using a remote device that can transform the scattered light outside a virtual boundary into that of the object chosen for the illusion, irrespective of the profile and direction of the incident light. This type of illusion device also enables people to see through walls. Our work extends the concept of cloaking as a special form of illusion to the wider realm of illusion optics.

Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time $T_2$ of a spin system. We report on the experimental implementation of all-optical spin echo to determine the $T_2$ time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an echo signal as the time between pulses is lengthened. Unlike previous spin-echo techniques using microwaves, ultrafast optical pulses allow clean $T_2$ measurements of systems with dephasing times ($T_2^{*}$) fast in comparison to the time scale for microwave control. This demonstration provides a step toward ultrafast optical dynamic decoupling of spin-based qubits.

A new experimental approach is introduced to probe the rheology of $\gtrsim 100\mathrm{nm}$-thick liquid polymer films. As-cast films were found to have a substantially reduced effective viscosity compared to annealed films. The reduced viscosity is explained in terms of nonequilibrium chain conformations giving rise to a reduced entanglement density caused by the rapid quenching of the film during spin coating. Unexpectedly long annealing times at high temperatures are required for the films to recover their bulk rheology.

We study the scaling properties of critical particle systems confined by a potential. Using renormalization-group arguments, we show that their critical behavior can be cast in the form of a trap-size scaling, resembling finite-size scaling theory, with a nontrivial trap critical exponent $\theta$, which describes how the correlation length $\xi$ scales with the trap size $l$, i.e., $\xi \sim l^{\theta }$ at $T_c$. $\theta$ depends on the universality class of the transition, the power law of the confining potential, and on the way it is coupled to the critical modes. We present numerical results for two-dimensional lattice gas (Ising) models with various types of harmonic traps, which support the trap-size scaling scenario.

In CDF we have observed the reactions $p+\overline{p}\to p+X+\overline{p}$, with $X$ being a centrally produced $J/\psi$, $\psi (2S)$, or ${\chi }_{c0}$, and $\gamma \gamma \to {\mu }^{+}{\mu }^{-}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$. The event signature requires two oppositely charged central muons, and either no other particles or one additional photon detected. Exclusive vector meson production is as expected for elastic photoproduction, $\gamma +p\to J/\psi \mathbf{(}\psi (2S)\mathbf{)}+p$, observed here for the first time in hadron-hadron collisions. We also observe exclusive ${\chi }_{c0}\to J/\psi +\gamma$. The cross sections $\frac{d\sigma }{dy}{|}_{y=0}$ for $J/\psi$, $\psi (2S)$, and ${\chi }_{c0}$ are $3.92\pm 0.25(\mathrm{stat})\pm 0.52(\mathrm{syst})\mathrm{nb}$, $0.53\pm 0.09(\mathrm{stat})\pm 0.10(\mathrm{syst})\mathrm{nb}$, and $76\pm 10(\mathrm{stat})\pm 10(\mathrm{syst})\mathrm{nb}$, respectively, and the continuum is consistent with QED. We put an upper limit on the cross section for Odderon exchange in exclusive $J/\psi$ production.

We propose an explanation for the long-standing puzzles of the microscopic mechanism of chain friction and the failure of time-temperature superposition in polymer melts based on decoupling of macromolecular scale diffusion from local structural relaxation due to spatially heterogeneous dynamics. The proposed physical picture is also relevant for understanding some aspects of dynamic fluctuation and decoupling phenomena in nonpolymeric glass-forming liquids, crystal growth rates, and protein activity in viscous solvents.

Using a novel morphology segregation technique, we observed minority populations ($\approx 3\%$) of submicron-sized, cluster-dilute fractal-like aggregates, formed in the soot-formation window (fuel-to-air equivalence ratio of 2.0–3.5) of a premixed flame, to have mass fractal dimensions between 1.2 and 1.51. Our observations disagree with previous observations of a universal mass fractal dimension of $\approx 1.8$ for fractal-like aerosol aggregates formed in the dilute-limit via three-dimensional diffusion-limited cluster aggregation processes. A hypothesis is presented to explain this observation. Subject to verification of this hypothesis, it may be possible to control the fractal dimension and associated properties of aggregates in the cluster-dilute limit through application of a static electric field during the aggregation process.

We report the first direct determination of the dissipation range of magnetofluid turbulence in the solar wind at the electron scales. Combining high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectrum of turbulence and found two distinct breakpoints in the magnetic spectrum at 0.4 and 35 Hz, which correspond, respectively, to the Doppler-shifted proton and electron gyroscales, $f_{{\rho }_p}$ and $f_{{\rho }_e}$. Below $f_{{\rho }_p}$, the spectrum follows a Kolmogorov scaling $f^{-1.62}$, typical of spectra observed at 1 AU. Above $f_{{\rho }_p}$, a second inertial range is formed with a scaling $f^{-2.3}$ down to $f_{{\rho }_e}$. Above $f_{{\rho }_e}$, the spectrum has a steeper power law $\sim f^{-4.1}$ down to the noise level of the instrument. We interpret this as the dissipation range and show a remarkable agreement with theoretical predictions of a quasi-two-dimensional cascade into Kinetic Alfvén Waves (KAW).

We have observed Fermi polarons, dressed spin-down impurities in a spin-up Fermi sea of ultracold atoms. The polaron manifests itself as a narrow peak in the impurities’ rf spectrum that emerges from a broad incoherent background. We determine the polaron energy and the quasiparticle residue for various interaction strengths around a Feshbach resonance. At a critical interaction, we observe the transition from polaronic to molecular binding. Here, the imbalanced Fermi liquid undergoes a phase transition into a Bose liquid, coexisting with a Fermi sea.

We propose the general concept of cloaking a sensor without affecting its capability to receive, measure, and observe an incoming signal. This may be obtained by using a plasmonic sensor, based on cloaking, made of materials available in nature at infrared and optical frequencies, or realizable as a metamaterial at lower frequencies. The result is a sensing system that may receive and transmit information, while its presence is not perceived by the surrounding, which may be of fundamental importance in a wide range of biological, optics, physics, and engineering applications.

Many-body entangled quantum states studied in condensed matter physics can be primary resources for quantum information, allowing any quantum computation to be realized using measurements alone, on the state. Such a universal state would be remarkably valuable, if only it were thermodynamically stable and experimentally accessible, by virtue of being the unique ground state of a physically reasonable Hamiltonian made of two-body, nearest-neighbor interactions. We introduce such a state, composed of six-state particles on a hexagonal lattice, and describe a general method for analyzing its properties based on its projected entangled pair state representation.

Recent single molecule experiments have reported that DNA binding proteins (DNA-BPs) can diffuse along DNA. This suggests that interactions between proteins and DNA play a role during the target search even far from their specific site on DNA. Here we show by means of Monte Carlo simulations and analytical calculations that there is a counterintuitive repulsion between the two oppositely charged macromolecules at a nanometer range. For the concave shape of DNA-BPs, and for realistic protein charge densities, we find that the DNA-protein interaction free energy has a minimum at a finite surface-to-surface separation, in which proteins can easily slide. When a protein encounters its target, the free energy barrier is completely counterbalanced by the H-bond interaction, thus enabling the sequence recognition.

From an interplay of time-lapsed high resolution scanning tunneling microscopy and density functional theory calculations we reveal the formation and diffusion of water dimers on hydrated rutile ${\mathrm{TiO}}_2(110)\mathrm{\text{−}}(1\times 1)$ surfaces, i.e., surfaces containing ${\mathrm{OH}}_{\mathrm{br}}$ groups. At temperatures between $\sim 150$ and $\sim 210\mathrm{K}$ water monomers diffusing along the Ti troughs were found to form stable water dimers that diffuse faster than the water monomers. An H bond mediated rollover mechanism operating for the water dimers explains the experimental findings.