We present a comprehensive model for the nucleation of domains in membrane adhesion. We determine the critical number of bonds in a nucleus and calculate the probability distribution of nucleation time from a discrete master equation. The latter is characterized by only four effective rates, which account for cooperative effects between bonds. We validate our model by finding excellent agreement with extensive Langevin simulations. In the range of parameters typical for cell adhesion, we find the critical number of bonds to be small. Furthermore, we find a characteristic separation between the bonds at which nucleation is particularly fast, pointing to potential regulatory mechanisms that could be used to control the cell recognition processes.

Above a critical chemistry-dependent molecular weight, all polymer molecules entangle and, as a result, exhibit slow dynamics, enhanced viscosity, and elasticity. Herein we report on the dynamics of low molecular weight polymers tethered to nanoparticles and find that even conventionally unentangled chains manifest dynamical features similar to entangled, long-chain molecules. Our findings are shown to imply that crowding and confinement of polymers on particles produce topological constraints analogous to those in entangled systems.

Controlled dephasing of electrons, via “which path” detection, involves, in general, coupling a coherent system to a current driven noise source. However, here we present a case in which a nearly isolated electron puddle within a quantum dot, at thermal equilibrium and in millikelvin range temperature, fully dephases the interference in a nearby electronic interferometer. Moreover, the complete dephasing is accompanied by an abrupt $\pi$ phase slip, which is robust and nearly independent of system parameters. Attributing the robustness of the phenomenon to the Friedel sum rule—which relates a system’s occupation to its scattering phases—proves the universality of this powerful rule. The experiment allows us to peek into a nearly isolated quantum dot, which cannot be accessed via conductance measurements.

Path entanglement constitutes an essential resource in quantum information and communication protocols. Here, we demonstrate frequency-degenerate entanglement between continuous-variable quantum microwaves propagating along two spatially separated paths. We combine a squeezed and a vacuum state using a microwave beam splitter. Via correlation measurements, we detect and quantify the path entanglement contained in the beam splitter output state. Our experiments open the avenue to quantum teleportation, quantum communication, or quantum radar with continuous variables at microwave frequencies.

We study the large deviation statistics of the intensive work done by globally changing a control parameter in a thermally isolated quantum many-body system. We show that, upon approaching a critical point, large deviations well below the mean work display universal features related to the critical Casimir effect in the corresponding classical system. Large deviations well above the mean are, instead, of quantum nature and not captured by the quantum-to-classical correspondence. For a bosonic system we show that in this latter regime a transition from exponential to power-law statistics, analogous to the equilibrium Bose-Einstein condensation, may occur depending on the parameters of the quench and on the spatial dimensionality.

Eddington-inspired Born-Infeld gravity was recently proposed as an alternative to general relativity that offers a resolution of spacetime singularities. The theory differs from Einstein’s gravity only inside matter due to nondynamical degrees of freedom, and it is compatible with all current observations. We show that the theory is reminiscent of Palatini $f(\mathcal{R})$ gravity and that it shares the same pathologies, such as curvature singularities at the surface of polytropic stars and unacceptable Newtonian limit. This casts serious doubt on its viability.

In this Letter we report the first results on ${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\overline{p}$ production at midrapidity ($|y|<0.5$) in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76\mathrm{TeV}$, measured by the ALICE experiment at the LHC. The $p_{\mathrm{T}}$ distributions and yields are compared to previous results at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with $\sqrt{s_{\mathrm{NN}}}$, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the $K/\pi$ ratio is in line with predictions from the thermal model, the $p/\pi$ ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.

In the past few years, coupling strengths between light and mechanical motion in optomechanical setups have improved by orders of magnitude. Here we show that, in the standard setup under continuous laser illumination, the steady state of the mechanical oscillator can develop a nonclassical, strongly negative Wigner density if the optomechanical coupling is comparable to or larger than the optical decay rate and the mechanical frequency. Because of its robustness, such a Wigner density can be mapped using optical homodyne tomography. This feature is observed near the onset of the instability towards self-induced oscillations. We show that there are also distinct signatures in the photon-photon correlation function $g^{(2)}(t)$ in that regime, including oscillations decaying on a time scale not only much longer than the optical cavity decay time but even longer than the mechanical decay time.

We experimentally study the relaxation oscillations and amplitude stability properties of an optical laser operating deep into the bad-cavity regime using a laser-cooled ${}^{87}\mathrm{Rb}$ Raman laser. By combining measurements of the laser light field with nondemolition measurements of the atomic populations, we infer the response of the gain medium represented by a collective atomic Bloch vector. The results are qualitatively explained with a simple model. Measurements and theory are extended to include the effect of intermediate repumping states on the closed-loop stability of the oscillator and the role of cavity feedback on stabilizing or enhancing relaxation oscillations. This experimental study of the stability of an optical laser operating deep into the bad-cavity regime will guide future development of superradiant lasers with ultranarrow linewidths.

Coherent pulse control for quantum memory is viable in the optical domain but nascent in microwave quantum circuits. We show how to realize coherent storage and on-demand pulse retrieval entirely within a superconducting circuit by exploiting and extending existing electromagnetically induced transparency technology in superconducting quantum circuits. Our scheme employs a linear array of superconducting artificial atoms coupled to a microwave transmission line.

Entangled states of light including low-loss optical fiber transmission and atomic resonance frequencies are essential resources for future quantum information networks. We present the experimental achievement on the three-color entanglement generation at 852, 1550, and 1440 nm wavelengths for optical continuous variables. The entanglement generation system consists of two cascaded nondegenerated optical parametric oscillators (NOPOs). The flexible selectivity of nonlinear crystals in the two NOPOs and the tunable property of NOPO provide large freedom for the frequency selection of three entangled optical beams. The presented system will hopefully be developed as a practical entangled source to be used in quantum-information networks with atomic storage units and long fiber transmission lines.

We demonstrate the realization of a coherent random fiber laser (RFL) in the extremely weakly scattering regime, which contains a dispersive solution of polyhedral oligomeric silsesquioxanes nanoparticles (NPs) and laser dye pyrromethene 597 in carbon disulfide that was injected into a hollow optical fiber. Multiple scattering of polyhedral oligomeric silsesquioxanes NPs greatly enhanced by the waveguide confinement effect was experimentally verified to account for coherent lasing observed in our RFL system. This Letter extends the NPs-based RFLs from the incoherent regime to the coherent regime.

We present experimental and numerical results on intense-laser-pulse-produced fast electron beams transport through aluminum samples, either solid or compressed and heated by laser-induced planar shock propagation. Thanks to absolute $K_{\alpha }$ yield measurements and its very good agreement with results from numerical simulations, we quantify the collisional and resistive fast electron stopping powers: for electron current densities of $\approx 8\times {10}^{10}\mathrm{A}/{\mathrm{cm}}^2$ they reach $1.5\mathrm{keV}/\mu \mathrm{m}$ and $0.8\mathrm{keV}/\mu \mathrm{m}$, respectively. For higher current densities up to ${10}^{12}\mathrm{A}/{\mathrm{cm}}^2$, numerical simulations show resistive and collisional energy losses at comparable levels. Analytical estimations predict the resistive stopping power will be kept on the level of $1\mathrm{keV}/\mu \mathrm{m}$ for electron current densities of ${10}^{14}\mathrm{A}/{\mathrm{cm}}^2$, representative of the full-scale conditions in the fast ignition of inertially confined fusion targets.

Electron dephasing is a major gain-inhibiting effect in plasma-based accelerators. A novel method is proposed to overcome dephasing, in which the modulation of a modest [$\sim \mathcal{O}(10\mathrm{kG})$], axial, uniform magnetic field in the acceleration channel leads to densification of the plasma through magnetic compression, enabling direct, time-resolved control of the plasma wave properties. The methodology is broadly applicable and can be optimized to improve the leading acceleration approaches, including plasma beat wave, plasma wakefield, and laser wakefield acceleration. The advantages of magnetic compression are compared to other proposed techniques to overcome dephasing.

FeRh undergoes an unusual antiferromagnetic-to-ferromagnetic (AFM-FM) transition just above room temperature ($T_{\mathrm{AFM}>\mathrm{FM}}$) that can be tuned or even completely suppressed with small changes in composition. The underlying temperature-dependent entropy difference between the competing AFM and FM states that drives this transition is measured by specific heat as a function of temperature from 2 to 380 K on two nearly equiatomic epitaxial Fe-Rh films, one with a ferromagnetic ground state (Fe-rich) and the other with an antiferromagnetic ground state (Rh-rich). The FM state shows an excess heat capacity near 100 K associated with magnetic excitations that are not present in the AFM state. The integrated entropy and enthalpy differences between the two alloys up to $T_{\mathrm{AFM}>\mathrm{FM}}$ agree with the previously measured entropy of the transition ($\Delta S=17\pm 3\mathrm{J}/\mathrm{kg}/\mathrm{K}$) and yield a $T=0$ energy difference of $3.4\mathrm{J}/\mathrm{g}$, consistent with literature calculations and experimental data; this agreement supports the use of the Fe-rich FM sample as a proxy for the (unstable) FM state of the AFM Rh-rich sample. From the low-temperature specific heat, along with sound velocity and photoemission measurements, the lattice contribution to the difference ($\Delta S_{\mathrm{latt}}=-33\pm 9\mathrm{J}/\mathrm{kg}/\mathrm{K}$) and electronic contribution ($\Delta S_{\mathrm{el}}=8\pm 1\mathrm{J}/\mathrm{kg}/\mathrm{K}$) to the difference in entropy are calculated, from which the excess heat capacity in the FM phase and the resulting entropy difference are shown to be dominated by magnetic fluctuations ($\Delta S_{\mathrm{mag}}=43\pm 9\mathrm{J}/\mathrm{kg}/\mathrm{K}$). The excess magnetic heat capacity is dominated by the magnetic heat capacity of the FM phase, which can be fit to a Schottky-like anomaly with an energy splitting of $16\pm 1\mathrm{meV}$ and a multiplicity of 1 per unit cell.

Coherent x-ray diffraction experiments have been used to probe the dynamics of the charge density wave (CDW) in the quasi-1D system ${\mathrm{NbSe}}_3$. The $2k_F$ satellite reflection associated with the CDW has been measured with respect to external dc currents, below and above the depinning current. These measurements illustrate for the first time the extensive behavior of a moving electronic crystal: the creep regime, with nucleation of CDW dislocations, the flow regime, with motional ordering, along with phase slippage and the role of strong pinning due to an extrinsic defect.

We predict that an incompressible fractional quantum Hall state is likely to form at $\nu =3/8$ as a result of a chiral $p$-wave pairing of fully spin polarized composite fermions carrying four quantized vortices, and that the pairing is of the anti-Pfaffian kind. Experimental ramifications include quasiparticles with non-Abelian braid statistics and upstream neutral edge modes.

Nanoscale systems of metal atoms antiferromagnetically exchange coupled to several magnetic impurities are shown to exhibit an unconventional reentrant competition between Kondo screening and indirect magnetic exchange interaction. Depending on the atomic positions of the magnetic moments, the total ground-state spin deviates from predictions of standard Ruderman-Kittel-Kasuya-Yosida perturbation theory. The effect shows up on an energy scale larger than the level width induced by the coupling to the environment and is experimentally accessible by studying magnetic field dependencies.

Herein, we predict that a 1D chain of $\mathrm{Ti}@{\mathrm{C}}_{32}-{\mathrm{C}}_2-\mathrm{Ti}@{\mathrm{C}}_{32}$ (TEMF) will act as a spin switch in the presence of an electric field. The spin resolved density of states analyses reveal that, surprisingly, both the low- and high-spin states of TEMF are half-metal; however, the metallic density of states comes from the opposite spin channels of the two spin states. More remarkably, it is found that the electric field driven spin crossover between the low and high state in TEMF is achievable at field strength $1.04\mathrm{V}/\mathrm{nm}$, which eventually leads to the realization of the first ever electrically operated spin switch device.

Temperature- and magnetic-field-dependent measurements of the loss tangent in $\mathrm{Ba}({\mathrm{Zn}}_{1/3}{\mathrm{Ta}}_{2/3}){\mathrm{O}}_3$ doped with transition metals (Mn, Ni) are compared to those from samples doped with other impurities (Cd, Ga, Mg, and Zr). These results, combined with pulsed electron paramagnetic resonance measurements, show conclusively that microwave loss in transition-metal-doped $\mathrm{Ba}({\mathrm{Zn}}_{1/3}{\mathrm{Ta}}_{2/3}){\mathrm{O}}_3$ at cryogenic temperatures is attributable to resonant spin excitations of unpaired transition-metal $d$ electrons in isolated atoms (light doping) or exchange coupled clusters (moderate to high doping), a mechanism that differs from the usual suspects.