In a supersymmetric theory, the IR contributions to the Higgs mass are calculable below the mediation scale ${\mathrm{\Lambda }}_{\mathrm{UV}}$ in terms of the IR field content and parameters. However, logarithmic sensitivity to physics at ${\mathrm{\Lambda }}_{\mathrm{UV}}$ remains. In this Letter, we present a first example of a framework, dictated by symmetries, to supersoften these logarithms from the matter sector. The result is a model with finite, IR-calculable corrections to the Higgs mass. This requires the introduction of new fields—the “lumberjacks”—whose role is to screen the UV-sensitive logs. These models have considerably reduced fine-tuning, by more than an order of magnitude for high-scale supersymmetry. This impacts interpretations of the natural parameter space, suggesting it may be premature to declare a naturalness crisis for high-scale supersymmetry.

Using a data sample of proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$, corresponding to an integrated luminosity of $140{\mathrm{fb}}^{-1}$ collected by the CMS experiment in 2016–2018, the $B_s^0\to X(3872)\varphi$ decay is observed. Decays into $J/\psi {\pi }^{+}{\pi }^{-}$ and $K^{+}{K}^{-}$ are used to reconstruct, respectively, the $X(3872)$ and $\varphi$. The ratio of the product of branching fractions $\mathcal{B}[B_s^0\to X(3872)\varphi ]\mathcal{B}[X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}]$ to the product $\mathcal{B}[B_s^0\to \psi (2S)\varphi ]\mathcal{B}[\psi (2S)\to J/\psi {\pi }^{+}{\pi }^{-}]$ is measured to be $[2.21\pm 0.29(\mathrm{stat})\pm 0.17(\mathrm{syst})]\%$. The ratio $\mathcal{B}[B_s^0\to X(3872)\varphi ]/\mathcal{B}[B^0\to X(3872)K^0]$ is found to be consistent with one, while the ratio $\mathcal{B}[B_s^0\to X(3872)\varphi ]/\mathcal{B}[B^{+}\to X(3872)K^{+}]$ is two times smaller. This suggests a difference in the production dynamics of the $X(3872)$ in $B^0$ and $B_s^0$ meson decays compared to $B^{+}$. The reported observation may shed new light on the nature of the $X(3872)$ particle.

High-pressure metallic $\beta \text{−}\mathrm{Sn}$ silicon (Si-II), depending on temperature, decompression rate, stress, etc., may transform to diverse metastable forms with promising semiconducting properties under decompression. However, the underlying mechanisms governing the different transformation paths are not well understood. Here, two distinctive pathways, viz., a thermally activated crystal-crystal transition and a mechanically driven amorphization, were characterized under rapid decompression of Si-II at various temperatures using in situ time-resolved x-ray diffraction. Under slow decompression, Si-II transforms to a crystalline bc8/r8 phase in the pressure range of 4.3–9.2 GPa through a thermally activated process where the overdepressurization and the onset transition strain are strongly dependent on decompression rate and temperature. In comparison, Si-II collapses structurally to an amorphous form at around 4.3 GPa when the volume expansion approaches a critical strain via rapid decompression beyond a threshold rate. The occurrence of the critical strain indicates a limit of the structural metastability of Si-II, which separates the thermally activated and mechanically driven transition processes. The results show the coupled effect of decompression rate, activation barrier, and thermal energy on the adopted transformation paths, providing atomistic insight into the competition between equilibrium and nonequilibrium pathways and the resulting metastable phases.

The thinning and rupture of thin liquid films is a ubiquitous process, controlling the lifetime of bubbles, antibubbles, and droplets. A better understanding of rupture is important for controlling and modeling the stability of multiphase products. Yet literature reports that film breakup can be either stochastic or deterministic. Here, we employ a modified thin film balance to vary the ratio of hydrodynamic to capillary stresses and its role on the dynamics of thin liquid films of polymer solutions with adequate viscosities. Varying the pressure drop across planar films allows us to control the ratio of the two competing timescales, i.e., a controlled hydrodynamic drainage time and a timescale related to fluctuations. The thickness fluctuations are visualized and quantified, and their characteristics are for the first time directly measured experimentally for varying strengths of the flow inside the film. We show how the criteria for rupture depend on the hydrodynamic conditions, changing from stochastic to deterministic as the hydrodynamic forces inside the film damp the fluctuations.

Certifying that quantum devices behave as intended is crucial for quantum information science. Here, methods are developed for certification of both state preparation devices and measurement devices based on prepare-and-measure experiments with independent devices. The experimenter assumes the independence of the devices and knowledge of the Hilbert space dimension. Thus no precise characterization of any part of the experiment is required. The certification is based on a randomized version of unambiguous state discrimination and targets the class of state ensembles corresponding to quantum $t$ designs of any size and any dimension. These quantum designs are sets of states over which the average of any $t$-degree polynomial equals its average over all pure states, and they accommodate many of the most useful discrete structures in quantum information processing. Furthermore, it is shown that the same experiments also certify the detection efficiency of the measurement devices, as well as their nonprojective nature. The presented methods can readily be implemented in experiments.

Limited quantum memory is one of the most important constraints for near-term quantum devices. Understanding whether a small quantum computer can simulate a larger quantum system, or execute an algorithm requiring more qubits than available, is both of theoretical and practical importance. In this Letter, we introduce cluster parameters $K$ and $d$ of a quantum circuit. The tensor network of such a circuit can be decomposed into clusters of size at most $d$ with at most $K$ qubits of inter-cluster quantum communication. We propose a cluster simulation scheme that can simulate any $(K,d)$-clustered quantum circuit on a $d$-qubit machine in time roughly $2^{O(K)}$, with further speedups possible when taking more fine-grained circuit structure into account. We show how our scheme can be used to simulate clustered quantum systems—such as large molecules—that can be partitioned into multiple significantly smaller clusters with weak interactions among them. By using a suitable clustered ansatz, we also experimentally demonstrate that a quantum variational eigensolver can still achieve the desired performance for estimating the energy of the ${\mathrm{BeH}}_2$ molecule while running on a physical quantum device with half the number of required qubits.

In a large scale trapped atomic ion quantum computer, high-fidelity two-qubit gates need to be extended over all qubits with individual control. We realize and characterize high-fidelity two-qubit gates in a system with up to four ions using radial modes. The ions are individually addressed by two tightly focused beams steered using microelectromechanical system mirrors. We deduce a gate fidelity of 99.49(7)% in a two-ion chain and 99.30(6)% in a four-ion chain by applying a sequence of up to 21 two-qubit gates and measuring the final state fidelity. We characterize the residual errors and discuss methods to further improve the gate fidelity towards values that are compatible with fault-tolerant quantum computation.

A liquid carbon ($l$-C) sample is generated through constant volume heating exposing an amorphous carbon foil to an intense ultrashort laser pulse. Time-resolved x-ray absorption spectroscopy at the C $K$ edge is used to monitor the dynamics of the melting process revealing a subpicosecond rearrangement of the electronic structure associated with a sudden change of the C bonding hybridization. The obtained $l$-C sample, resulting from a nonthermal melting mechanism, reaches a transient equilibrium condition with a temperature of about 14 200 K and pressure in the order of 0.5 Mbar in about 0.3 ps, prior to hydrodynamic expansion. A detailed analysis of the atomic and electronic structure in solid-density $l$-C based on time-resolved x-ray absorption spectroscopy and theoretical simulations is presented. The method can be fruitfully used for extending the experimental investigation of the C phase diagram in a vast unexplored region covering the ${10}^3–{10}^4\mathrm{K}$ temperature range with pressures up to 1 Mbar.

Atomic-scale interaction of water vapor with metal surfaces beyond surface adsorption under technologically relevant conditions remains mostly unexplored. Using aberration-corrected environmental transmission electron microscopy, we reveal the dynamic surface activation of Cu by ${\mathrm{H}}_2\mathrm{O}$ at elevated temperature and pressure. We find a structural transition from flat to corrugated surface for the Cu(011) under low water-vapor pressure. Increasing the water-vapor pressure leads to the surface reaction of Cu with dissociated ${\mathrm{H}}_2\mathrm{O}$, resulting in the formation of a metastable “bilayer” $\mathrm{Cu}─\mathrm{O}─\mathrm{H}$ phase. Corroborated by density functional theory and ab initio molecular dynamics calculations, the cooperative O and OH interaction with Cu is responsible for the formation and subsurface propagation of this phase.

We explore intrinsic thermal noise in soliton microcombs, revealing thermodynamic correlations induced by nonlinearity and group-velocity dispersion. A suitable dispersion design gives rise to control over thermal-noise transduction from the environment to a soliton microcomb. We present simulations with the Lugiato-Lefever equation (LLE), including temperature as a stochastic variable. By systematically tuning the dispersion, we suppress repetition-rate frequency fluctuations by up to 50 decibels for different LLE soliton solutions. In an experiment, we observe a measurement-system-limited 15-decibel reduction in the repetition-rate phase noise for various settings of the pump-laser frequency, and our measurements agree with a thermal-noise model. Finally, we compare two octave-spanning soliton microcombs with similar optical spectra and offset frequencies, but with designed differences in dispersion. Remarkably, their thermal-noise-limited carrier-envelope-offset frequency linewidths are 1 MHz and 100 Hz, which demonstrates an unprecedented potential to mitigate thermal noise. Our results guide future soliton-microcomb design for low-noise applications, and, more generally, they illuminate emergent properties of nonlinear, multimode optical systems subject to intrinsic fluctuations.

We study the delocalization dynamics of interacting disordered hard-core bosons for quasi-1D and 2D geometries, with system sizes and timescales comparable to state-of-the-art experiments. The results are strikingly similar to the 1D case, with slow, subdiffusive dynamics featuring power-law decay. From the freezing of this decay we infer the critical disorder $W_c(L,d)$ as a function of length $L$ and width $d$. In the quasi-1D case $W_c$ has a finite large-$L$ limit at fixed $d$, which increases strongly with $d$. In the 2D case $W_c(L,L)$ grows with $L$. The results are consistent with the avalanche picture of the many-body localization transition.

We suggest a new spin orientation mechanism for localized electrons: dynamic electron spin polarization provided by nuclear spin fluctuations. The detrimental effect of nuclear spin fluctuations can be harnessed and employed to provide angular momentum for the electrons via the hyperfine interaction in a weak magnetic field. For this, the sample is illuminated by an unpolarized light, which directly polarizes neither the electrons nor the nuclei. We predict that, for the electrons bound in localized excitons, 100% spin polarization can be reached in longitudinal magnetic fields of a few millitesla. The proof of principle experiment is performed on momentum-indirect excitons in $(\mathrm{In},\mathrm{Al})\mathrm{As}/\mathrm{AlAs}$ quantum dots, where in a magnetic field of 17 mT the electron spin polarization of 30% is measured.

We investigate the pressure effects on the electronic structures and phonon properties of rare-earth-based cubic-Heusler compound ${\mathrm{LuPd}}_2\mathrm{In}$, on the basis of $ab$ $initio$ density functional theory. We find the occurrence of intriguing phase transition from the superconducting (SC) to charge-density wave (CDW) state under pressure ($P$), which is quite unusual in that the pressure is detrimental to the CDW state in usual systems. The SC transition temperature $T_C$ of ${\mathrm{LuPd}}_2\mathrm{In}$ increases first with increasing pressure, up to $P_C\approx 28\mathrm{GPa}$, above which a quantum phase transition into the CDW state takes place. This extraordinary transition originates from the occurrence of phonon softening instability at a special $\mathbf{q}=M$ in the Brillouin zone. We thus propose that ${\mathrm{LuPd}}_2\mathrm{In}$ is a quite unique material, in which the CDW quantum critical point is realized under the SC dome by applying the pressure.

The spatially confined evanescent modes in near-field photonics have been proved to be highly desirable in broad practical scenarios ranging from robust information communications to efficient quantum interactions. However, the feasible applications of these photonics modes are limited due to the lack of fundamental understanding and feasible directional coupling approaches at subwavelengths. Here, we propose all-electric near-field metasources in subwavelength scale without mimicking the polarization features or introducing magnetic dipoles. The near-field selective functions of metasources corresponding to time-reversal, parity-time, and parity symmetries of their inner degree of freedom are exemplified in various optical systems. We experimentally demonstrate the efficient near-field photonic routing achieved in waveguides composed of two kinds of single-negative metamaterials. Our work furthers the understanding of optical near-field symmetry and feasible engineering approaches of directional couplings, which would pave the way for promising integrated near-field photonics devices.

This Letter presents a neural estimator for entropy production (NEEP), that estimates entropy production (EP) from trajectories of relevant variables without detailed information on the system dynamics. For steady state, we rigorously prove that the estimator, which can be built up from different choices of deep neural networks, provides stochastic EP by optimizing the objective function proposed here. We verify the NEEP with the stochastic processes of the bead spring and discrete flashing ratchet models and also demonstrate that our method is applicable to high-dimensional data and can provide coarse-grained EP for Markov systems with unobservable states.

Zel’dovich proposed that electromagnetic (EM) waves with angular momentum reflected from a rotating metallic, lossy cylinder will be amplified. However, we are still lacking a direct experimental EM-wave verification of this fifty-year-old prediction due to the challenging conditions in which the phenomenon manifests itself: the mechanical rotation frequency of the cylinder must be comparable with the EM oscillation frequency. Here, we propose an experimental approach that solves this issue and is predicted to lead to a measurable Zel’dovich amplification with existing superconducting circuit technology. We design a superconducting circuit with low frequency EM modes that couple through free space to a magnetically levitated and spinning microsphere placed at the center of the circuit. We theoretically estimate the circuit EM mode gain and show that rotation of the microsphere can lead to experimentally observable amplification, thus paving the way for the first EM-field experimental demonstration of Zel’dovich amplification.