Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking (EWSB). All known ultraviolet completions of TH models require some nonperturbative dynamics below the Planck scale. We propose a supersymmetric model in which the TH mechanism is introduced by a new asymptotically free gauge interaction. The model features natural EWSB for squarks and gluino heavier than 2 TeV even if supersymmetry breaking is mediated around the Planck scale, and has interesting flavor phenomenology including the top quark decay into the Higgs boson and the up quark which may be discovered at the LHC.

The $\mathrm{\Omega }\mathrm{\Omega }$ system in the ${}^1{S}_0$ channel (the most strange dibaryon) is studied on the basis of the ($2+1$)-flavor lattice QCD simulations with a large volume $(8.1\mathrm{fm}{)}^3$ and nearly physical pion mass $m_{\pi }\simeq 146\mathrm{MeV}$ at a lattice spacing of $a\simeq 0.0846\mathrm{fm}$. We show that lattice QCD data analysis by the HAL QCD method leads to the scattering length $a_0=4.6(6){(}_{-0.5}^{+1.2})\mathrm{fm}$, the effective range $r_{\mathrm{eff}}=1.27(3){(}_{-0.03}^{+0.06})\mathrm{fm}$, and the binding energy $B_{\mathrm{\Omega }\mathrm{\Omega }}=1.6(6){(}_{-0.6}^{+0.7})\mathrm{MeV}$. These results indicate that the $\mathrm{\Omega }\mathrm{\Omega }$ system has an overall attraction and is located near the unitary regime. Such a system can be best searched experimentally by the pair-momentum correlation in relativistic heavy-ion collisions.

Ground-state two-proton ($2p$) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The $2p$ decay lifetime and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. The recently measured $2p$ decay of ${}^{67}\mathrm{Kr}$ turned out to be unexpectedly fast. Since ${}^{67}\mathrm{Kr}$ is expected to be a deformed system, we investigate the impact of deformation effects on the $2p$ radioactivity. We apply the recently developed Gamow coupled-channel framework, which allows for a precise description of three-body systems in the presence of rotational and vibrational couplings. This is the first application of a three-body approach to a two-nucleon decay from a deformed nucleus. We show that deformation couplings significantly increase the $2p$ decay width of ${}^{67}\mathrm{Kr}$; this finding explains the puzzling experimental data. The calculated angular proton-proton correlations reflect a competition between $1p$ and $2p$ decay modes in this nucleus.

High-dimensional quantum information processing promises capabilities beyond the current state of the art, but addressing individual information-carrying modes presents a significant experimental challenge. Here we demonstrate effective high-dimensional operations in the time-frequency domain of nonclassical light. We generate heralded photons with tailored temporal-mode structures through the pulse shaping of a broadband parametric down-conversion pump. We then implement a quantum pulse gate, enabled by dispersion-engineered sum-frequency generation, to project onto programmable temporal modes, reconstructing the quantum state in seven dimensions. We also manipulate the time-frequency structure by selectively removing temporal modes, explicitly demonstrating the effectiveness of engineered nonlinear processes for the mode-selective manipulation of quantum states.

Glassy carbon is a technologically important material with isotropic properties that is nongraphitizing up to $\sim 3000°\mathrm{C}$ and displays complete or “superelastic” recovery from large compression. The pressure limit of these properties is not yet known. Here we use experiments and modeling to show permanent densification, and preferred orientation occurs in glassy carbon loaded to 45 GPa and above, where 45 GPa represents the limit to the superelastic and nongraphitizing properties of the material. The changes are explained by a transformation from its $s{p}^2$ rich starting structure to a $s{p}^3$ rich phase that reverts to fully $s{p}^2$ bonded oriented graphite during pressure release.

We observe strong interlayer magnon-magnon coupling in an on-chip nanomagnonic device at room temperature. Ferromagnetic nanowire arrays are integrated on a 20-nm-thick yttrium iron garnet (YIG) thin film strip. Large anticrossing gaps up to 1.58 GHz are observed between the ferromagnetic resonance of the nanowires and the in-plane standing spin waves of the YIG film. Control experiments and simulations reveal that both the interlayer exchange coupling and the dynamical dipolar coupling contribute to the observed anticrossings. The coupling strength is tunable by the magnetic configuration, allowing the coherent control of magnonic devices.

We demonstrate that light resonant with the band gap forces the antiferromagnetic semiconductor EuSe to enter ferromagnetic alignment in the picosecond timescale. A photon generates an electron-hole pair, whose electron forms a supergiant spin polaron of magnetic moment of nearly 6000 Bohr magnetons. By increasing the light intensity, the whole of the illuminated region can be fully magnetized. The key to the novel large photoinduced magnetization mechanism is the huge enhancement of the magnetic susceptibility when both antiferromagnetic and ferromagnetic interactions are present in the material and are of nearly equal magnitude, as is the case in EuSe.

Magnetic droplets are nontopological dynamical solitons that can be nucleated in nanocontact based spin torque nano-oscillators (STNOs) with perpendicular magnetic anisotropy free layers. While theory predicts that the droplet should be of the same size as the nanocontact, its inherent drift instability has thwarted attempts at observing it directly using microscopy techniques. Here, we demonstrate highly stable magnetic droplets in all-perpendicular STNOs and present the first detailed droplet images using scanning transmission X-ray microscopy. In contrast to theoretical predictions, we find that the droplet diameter is about twice as large as the nanocontact. By extending the original droplet theory to properly account for the lateral current spread underneath the nanocontact, we show that the large discrepancy primarily arises from current-in-plane Zhang-Li torque adding an outward pressure on the droplet perimeter. Electrical measurements on droplets nucleated using a reversed current in the antiparallel state corroborate this picture.

We provide a generic scheme to separate the particles of a mixture by their physical properties like mass, friction, or size. The scheme employs a periodically shaken two-dimensional dissipative lattice and hinges on a simultaneous transport of particles in species-specific directions. This selective transport is achieved by controlling the late-time nonlinear particle dynamics, via the attractors embedded in the phase space and their bifurcations. To illustrate the spectrum of possible applications of the scheme, we exemplarily demonstrate the separation of polydisperse colloids and mixtures of cold thermal alkali atoms in optical lattices.

The dynamics of bosons in generic multimode systems, such as Bose-Hubbard models, are not only determined by interactions among the particles, but also by their mutual indistinguishability manifested in many-particle interference. We introduce a measure of indistinguishability for Fock states of bosons whose mutual distinguishability is controlled by an internal degree of freedom. We demonstrate how this measure emerges both in the noninteracting and interacting evolution of observables. In particular, we find an unambiguous relationship between our measure and the variance of single-particle observables in the noninteracting limit. A nonvanishing interaction leads to a hierarchy of interaction-induced interference processes, such that even the expectation value of single-particle observables is influenced by the degree of indistinguishability.

We describe a framework to reduce the computational effort to evaluate large deviation functions of time integrated observables within nonequilibrium steady states. We do this by incorporating an auxiliary dynamics into trajectory based Monte Carlo calculations, through a transformation of the system’s propagator using an approximate guiding function. This procedure importance samples the trajectories that most contribute to the large deviation function, mitigating the exponential complexity of such calculations. We illustrate the method by studying driven diffusion and interacting lattice models in one and two spatial dimensions. Our work offers an avenue to calculate large deviation functions for high dimensional systems driven far from equilibrium.

We propose a spatiotemporal quench protocol that allows for the fast preparation of ground states of gapless models with Lorentz invariance. Assuming the system initially resides in the ground state of a corresponding massive model, we show that a superluminally moving “front” that locally quenches the mass, leaves behind it (in space) a state arbitrarily close to the ground state of the gapless model. Importantly, our protocol takes time $\mathcal{O}(L)$ to produce the ground state of a system of size $\sim L^d$ ($d$ spatial dimensions), while a fully adiabatic protocol requires time $\sim \mathcal{O}(L^2)$ to produce a state with exponential accuracy in $L$. The physics of the dynamical problem can be understood in terms of relativistic rarefaction of excitations generated by the mass front. We provide proof of concept by solving the proposed quench exactly for a system of free bosons in arbitrary dimensions, and for free fermions in $d=1$. We discuss the role of interactions and UV effects on the free-theory idealization, before numerically illustrating the usefulness of the approach via simulations on the quantum Heisenberg spin chain.

We construct the exceptional sigma model: a two-dimensional sigma model coupled to a supergravity background in a manifestly (formally) $E_{D(D)}$-covariant manner. This formulation of the background is provided by exceptional field theory (EFT), which unites the metric and form fields of supergravity in $E_{D(D)}$ multiplets before compactification. The realization of the symmetries of EFT on the world sheet uniquely fixes the Weyl-invariant Lagrangian and allows us to relate our action to the usual type-IIA fundamental string action and a form of the type-IIB ($m$, $n$) action. This uniqueness “predicts” the correct form of the couplings to gauge fields in both Neveu-Schwarz and Ramond sectors, without invoking supersymmetry.

A direct search for the standard model Higgs boson decaying to a pair of charm quarks is presented. Associated production of the Higgs and $Z$ bosons, in the decay mode $ZH\to {\ell }^{+}{\ell }^{-}c\overline{c}$ is studied. A data set with an integrated luminosity of $36.1{\mathrm{fb}}^{-1}$ of $pp$ collisions at $\sqrt{s}=13\mathrm{TeV}$ recorded by the ATLAS experiment at the LHC is used. The $H\to c\overline{c}$ signature is identified using charm-tagging algorithms. The observed (expected) upper limit on $\sigma (pp\to ZH)\times \mathcal{B}(H\to c\overline{c})$ is 2.7 (${3.9}_{-1.1}^{+2.1}$) pb at the 95% confidence level for a Higgs boson mass of 125 GeV, while the standard model value is 26 fb.

A sequence of low-energy levels in ${{}_{32}{}^{78}\mathrm{Ge}}_{46}$ has been identified with spins and parity of $2^{+}$, $3^{+}$, $4^{+}$, $5^{+}$, and $6^{+}$. Decays within this band proceed strictly through $\mathrm{\Delta }J=1$ transitions, unlike similar sequences in neighboring Ge and Se nuclei. Above the $2^{+}$ level, members of this sequence do not decay into the ground-state band. Moreover, the energy staggering of this sequence has the phase that would be expected for a $\gamma$-rigid structure. The energies and branching ratios of many of the levels are described well by shell-model calculations. However, the calculated reduced transition probabilities for the $\mathrm{\Delta }J=2$ in-band transitions imply that they should have been observed, in contradiction with the experiment. Within the calculations of Davydov, Filippov, and Rostovsky for rigid-triaxial rotors with $\gamma =30°$, there are sequences of higher-spin levels connected by strong $\mathrm{\Delta }J=1$ transitions which decay in the same manner as those observed experimentally, yet are calculated at too high an excitation energy.

Two-photon Rabi splitting in a cavity-dot system provides a basis for multiqubit coherent control in a quantum photonic network. Here we report on two-photon Rabi splitting in a strongly coupled cavity-dot system. The quantum dot was grown intentionally large in size for a large oscillation strength and small biexciton binding energy. Both exciton and biexciton transitions couple to a high-quality-factor photonic crystal cavity with large coupling strengths over $130\mu \mathrm{eV}$. Furthermore, the small binding energy enables the cavity to simultaneously couple with two exciton states. Thereby, two-photon Rabi splitting between the biexciton and cavity is achieved, which can be well reproduced by theoretical calculations with quantum master equations.

We predict the onset of self-induced parametric or Faraday instabilities in a laser, spontaneously caused by the presence of pump depletion, which leads to a periodic gain landscape for light propagating in the cavity. As a result of the instability, continuous wave oscillation becomes unstable even in the normal dispersion regime of the cavity, and a periodic train of pulses with ultrahigh repetition rate is generated. Application to the case of Raman fiber lasers is described, in good quantitative agreement between our conceptual analysis and numerical modeling.

Symmetry broken states arise naturally in oscillatory networks. In this Letter, we investigate chaotic attractors in an ensemble of four mean-coupled Stuart-Landau oscillators with two oscillators being synchronized. We report that these states with partially broken symmetry, so-called chimera states, have different setwise symmetries in the incoherent oscillators, and in particular, some are and some are not invariant under a permutation symmetry on average. This allows for a classification of different chimera states in small networks. We conclude our report with a discussion of related states in spatially extended systems, which seem to inherit the symmetry properties of their counterparts in small networks.