The free-energy landscape of self-assembling block copolymer systems is characterized by a multitude of metastable minima. Using particle-based simulations of a soft, coarse-grained model, we explore opportunities to reproducibly direct the spontaneous ordering of these self-assembling systems into a metastable complex network morphology—specifically, Schoen’s I-WP periodic minimal surface—starting from a highly unstable state that is generated by a rapid expansion. This process-directed self-assembly provides an alternative to fine-tuning molecular architecture or blending for fabricating complex network structures. Comparing our particle-based simulation results to recently developed free-energy techniques, we critically assess their ability to predict spontaneous formation and highlight the importance of nonequilibrium molecular conformations in the starting state and the local conservation of density.

We study the nonequilibrium shape fluctuations in fluorescence labeled phospholipid multibilayers composed of the model lipid DOPC and the well-known lipid dye Texas red, driven out of equilibrium by short laser pulses. The temporal evolution of the lipid bilayer undulations after excitation was recorded by time resolved x-ray diffraction. Already at moderate peak intensities ($P_p\le {10}^5{\mathrm{W}/\mathrm{cm}}^2$), pulsed laser illumination leads to significant changes of the undulation modes in a well-defined lateral wavelength band. The observed phenomena evolve on nano- to microsecond time scales after optical excitation, and can be described in terms of a modulation instability in the lipid multilamellar stack.

The long time persistence of mechanical stresses is a generic property of glassy materials. Here we identify the microscopic mechanisms that control internal stresses in highly concentrated suspensions of soft particles brought to rest from steady flow. The persistence of the asymmetric angular distortions which characterize the pair distribution function during flow is at the origin of the internal stresses. Their long time evolution is driven by in-cage rearrangements of the elastic contacts between particles. The trapped macroscopic stress is related to the solvent viscosity, particle elasticity and volume fraction through a universal scaling derived from simulations and experiments.

We introduce an elasticity-based mechanism that drives active particles to self-organize by cascading self-propulsion energy towards lower-energy modes. We illustrate it on a simple model of self-propelled agents linked by linear springs that reach a collectively rotating or translating state without requiring aligning interactions. We develop an active elastic sheet theory, complementary to the prevailing active fluid theories, and find analytical stability conditions for the ordered state. Given its ubiquity, this mechanism could play a relevant role in various natural and artificial swarms.

Probes of cosmic expansion constitute the main basis for arguments to support or refute a possible apparent acceleration due to different expansion rates in the Universe as described by inhomogeneous cosmological models. We present in this Letter a separate argument based on results from an analysis of the growth rate of large-scale structure in the Universe as modeled by the inhomogeneous cosmological models of Szekeres. We use the models with no assumptions of spherical or axial symmetries. We find that while the Szekeres models can fit very well the observed expansion history without a $\mathrm{\Lambda }$, they fail to produce the observed late-time suppression in the growth unless $\mathrm{\Lambda }$ is added to the dynamics. A simultaneous fit to the supernova and growth factor data shows that the cold dark matter model with a cosmological constant ($\mathrm{\Lambda }\mathrm{CDM}$) provides consistency with the data at a confidence level of 99.65%, while the Szekeres model without $\mathrm{\Lambda }$ achieves only a 60.46% level. When the data sets are considered separately, the Szekeres with no $\mathrm{\Lambda }$ fits the supernova data as well as the $\mathrm{\Lambda }\mathrm{CDM}$ does, but provides a very poor fit to the growth data with only 31.31% consistency level compared to 99.99% for the $\mathrm{\Lambda }\mathrm{CDM}$. This absence of late-time growth suppression in inhomogeneous models without a is consolidated by a physical explanation.

Correlations in quantum systems exhibit a rich phenomenology under the effect of various sources of noise. We investigate theoretically and experimentally the dynamics of quantum correlations and their classical counterparts in two nuclear magnetic resonance setups, as measured by geometric quantifiers based on trace norm. We consider two-qubit systems prepared in Bell diagonal states, and perform the experiments in real decohering environments resulting from Markovian local noise which preserves the Bell diagonal form of the states. We then report the first observation of environment-induced double sudden transitions in the geometric quantum correlations, a genuinely nonclassical effect not observable in classical correlations. The evolution of classical correlations in our physical implementation reveals in turn the finite-time relaxation to a pointer basis under nondissipative decoherence, which we characterize geometrically in full analogy with predictions based on entropic measures.

I present a simple model that exhibits a temporal analogue of superconducting crystalline (Larkin-Ovchinnikov-Ferrell-Fulde) ordering, with a time-dependent order parameter. I sketch designs for minimally dissipative ac circuits, all based on time translation symmetry ($\tau$) invariant dynamics, exploiting weak links (Josephson effects). These systems violate $\tau$ spontaneously. I also discuss effective theories of that phenomenon, and space-time generalizations.

We develop the concept of genuine $N$-partite Einstein-Podolsky-Rosen (EPR) steering. This nonlocality is the natural multipartite extension of the original EPR paradox. Useful properties emerge that are not guaranteed for genuine multipartite entangled states. In particular, there is a close link with the task of one-sided, device-independent quantum secret sharing. We derive inequalities to demonstrate multipartite EPR steering for Greenberger-Horne-Zeilinger and Gaussian continuous variable states in loophole-free scenarios.

The ideas of thermodynamics have proved fruitful in the setting of quantum information theory, in particular the notion that when the allowed transformations of a system are restricted, certain states of the system become useful resources with which one can prepare previously inaccessible states. The theory of entanglement is perhaps the best-known and most well-understood resource theory in this sense. Here, we return to the basic questions of thermodynamics using the formalism of resource theories developed in quantum information theory and show that the free energy of thermodynamics emerges naturally from the resource theory of energy-preserving transformations. Specifically, the free energy quantifies the amount of useful work which can be extracted from asymptotically many copies of a quantum system when using only reversible energy-preserving transformations and a thermal bath at fixed temperature. The free energy also quantifies the rate at which resource states can be reversibly interconverted asymptotically, provided that a sublinear amount of coherent superposition over energy levels is available, a situation analogous to the sublinear amount of classical communication required for entanglement dilution.

Measurements of charm mixing parameters from the decay-time-dependent ratio of $D^0\to K^{+}{\pi }^{-}$ to $D^0\to K^{-}{\pi }^{+}$ rates and the charge-conjugate ratio are reported. The analysis uses data, corresponding to $3{\mathrm{fb}}^{-1}$ of integrated luminosity, from proton-proton collisions at 7 and 8 TeV center-of-mass energies recorded by the LHCb experiment. In the limit of charge-parity ($CP$ ) symmetry, the mixing parameters are determined to be $x^{\prime 2}=(5.5\pm 4.9)\times {10}^{-5}$, $y^{\prime }=(4.8\pm 1.0)\times {10}^{-3}$, and $R_D=(3.568\pm 0.066)\times {10}^{-3}$. Allowing for $CP$ violation, the measurement is performed separately for $D^0$ and ${\overline{D}}^0$ mesons yielding $A_D=(-0.7\pm 1.9)\%$, for the direct $CP$-violating asymmetry, and $0.75<|q/p|<1.24$ at the 68.3% confidence level, for the parameter describing $CP$ violation in mixing. This is the most precise determination of these parameters from a single experiment and shows no evidence for $CP$ violation.

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of ${}^6\mathrm{Li}$, ${}^8\mathrm{Be}$, and ${}^6\mathrm{He}$ are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.

Artificially implementing the biological light reactions responsible for the remarkably efficient photon-to-charge conversion in photosynthetic complexes represents a new direction for the future development of photovoltaic devices. Here, we develop such a paradigm and present a model photocell based on the nanoscale architecture and molecular elements of photosynthetic reaction centers. Quantum interference of photon absorption and emission induced by the dipole-dipole interaction between molecular excited states guarantees an enhanced light-to-current conversion and power generation for a wide range of electronic, thermal, and optical parameters for optimized dipolar geometries. This result opens a promising new route for designing artificial light-harvesting devices inspired by biological photosynthesis and quantum technologies.

We experimentally demonstrate that hybrid plasmon-photon modes exist in a silver-coated glass bottle resonator. The bottle resonator is realized in a glass fiber with a smoothly varying diameter, which is subsequently coated with a rhodamine 800-dye doped acryl-glass layer and a 30 nm thick silver layer. We show by means of photoluminescence experiments supported by electromagnetic simulations that the rhodamine 800 photoluminescence excites hybrid plasmon-photon modes in such a bottle resonator, which provide a plasmon-type field enhancement at the outer silver surface and exhibit quality factors as high as 1000.

Experimental results of a study of the electric field in a plasma channel produced during nanosecond discharge at a $H_2$ gas pressure of $(2-3)\times 10^5\mathrm{Pa}$ by the coherent anti-Stokes scattering method are reported. The discharge was ignited by applying a voltage pulse with an amplitude of $\sim 100\mathrm{kV}$ and a duration of $\sim 5\mathrm{ns}$ to a blade cathode placed at a distance of 10 and 20 mm from the anode. It was shown that this type of gas discharge is characterized by the presence of an electric field in the plasma channel with root-mean-square intensities of up to $30\mathrm{kV}/\mathrm{cm}$. Using polarization measurements, it was found that the direction of the electric field is along the cathode-anode axis.

The radiation emitted by $120\mathrm{GeV}/c$ electrons traversing a single bent crystal under multiple volume reflection orientation is investigated. Multiple volume reflection in one crystal occurs as a charged particle impacts on a bent crystal at several axial channeling angles with respect to a crystal axis. The resulting energy-loss spectrum of electrons was very intense over the full energy range up to the nominal energy of the beam. As compared to the radiation emission by an individual volume reflection, the energy-loss spectrum is more intense and peaks at an energy 3 times greater. Experimental results are compared to a theoretical approach based on the direct integration of the quasiclassical Baier and Katkov formula. In this way, it is possible to determine the mean number of photons emitted by each electron and, thus, to extract the single-photon spectrum, which is broad and intense. The soft part of the radiation spectrum is due to the contribution of coherent interaction between electrons and several reflecting planes intersecting the same crystal axis, whereas the hard part is mainly connected to coherent bremsstrahlung induced by correlated scattering of electrons by atomic strings (string of strings scattering and radiation). The radiation generation by multiple volume reflection takes place over a broad angular range of the incident beam with respect to coherent bremsstrahlung and channeling radiation in straight crystals. Therefore, this type of radiation can be exploited for applications, such as beam dump and collimation devices for future linear colliders.

The low-energy properties of one-dimensional quantum liquids are commonly described in terms of the Tomonaga-Luttinger liquid theory, in which the elementary excitations are free bosons. To this approximation, the theory can be alternatively recast in terms of free fermions. In both approaches, small perturbations give rise to finite lifetimes of excitations. We evaluate the decay rate of fermionic excitations and show that it scales as the eighth power of energy, in contrast to the much faster decay of bosonic excitations. Our results can be tested experimentally by measuring the broadening of power-law features in the density structure factor or spectral functions.

An analytical expression for the quantum breathing frequency ${\omega }_b$ of harmonically trapped quantum particles with inverse power-law repulsion is derived. It is verified by ab initio numerical calculations for electrons confined in a lateral (2D) quantum dot. We show how this relation can be used to express the ground state properties of harmonically trapped quantum particles as functions of the breathing frequency by presenting analytical results for the kinetic, trap, and repulsive energy and for the linear entropy. Measurement of ${\omega }_b$ together with these analytical relations represents a tool to characterize the state of harmonically trapped interacting particles—from the Fermi gas to the Wigner crystal regime.

The breakdown of magnons, the quasiparticles of magnetic systems, has rarely been seen. By using an inelastic neutron scattering technique, we report the observation of spontaneous magnon decay in multiferroic ${\mathrm{LuMnO}}_3$, a simple two dimensional Heisenberg triangular lattice antiferromagnet, with large spin $S=2$. The origin of this rare phenomenon lies in the nonvanishing cubic interaction between magnons in the spin Hamiltonian arising from the noncollinear 120° spin structure. We observed all three key features of the nonlinear effects as theoretically predicted: a rotonlike minimum, a flat mode, and a linewidth broadening, in our inelastic neutron scattering measurements of single crystal ${\mathrm{LuMnO}}_3$. Our results show that quasiparticles in a system hitherto thought of as “classical” can indeed break down.

The magnetic exchange in hole-doped ferromagnetic cobaltates is investigated by studying the magnetic and electronic properties of $\mathrm{L}{\mathrm{a}}_{0.7}\mathrm{S}{\mathrm{r}}_{0.3}\mathrm{Co}{\mathrm{O}}_3$ films as a function of epitaxial strain. We found a strong-coupling double exchange mechanism between ${\mathrm{Co}}^{3+}(4t_{2g}2e_g)$ and ${\mathrm{Co}}^{4+}(3t_{2g}2e_g)$ high-spin states mediated by $t_{2g}$ electrons—in contrast to the moderate coupling provided by the $e_g$ exchange in manganites. The strong sensitivity of the Curie temperature $T_C$ to the bulk compression can be explained by the small bandwidth of the $t_{2g}$-derived states. A strain-induced Jahn-Teller effect is likewise observed. The experimental results clarify the magnetic exchange mechanism in the cobaltates.

A unique spin depolarization mechanism, induced by the presence of $g$-factor anisotropy and intervalley scattering, is revealed by spin-transport measurements on long-distance germanium devices in a magnetic field longitudinal to the initial spin orientation. The confluence of electron-phonon scattering (leading to Elliott-Yafet spin flips) and this previously unobserved physics enables the extraction of spin lifetime solely from spin-valve measurements, without spin precession, and in a regime of substantial electric-field-generated carrier heating. We find spin lifetimes in Ge up to several hundreds of nanoseconds at low temperature, far beyond any other available experimental results.