Daviesclements1400

We introduce a framework to decompose a bosonic mode into two virtual subsystems-a logical qubit and a gauge mode. This framework allows the entire toolkit of qubit-based quantum information to be applied in the continuous-variable setting. We give a detailed example based on a modular decomposition of the position basis and apply it in two situations. First, we decompose Gottesman-Kitaev-Preskill grid states and find that the encoded logical state can be damaged due to entanglement with the gauge mode. Second, we identify and disentangle qubit cluster states hidden inside of Gaussian continuous-variable cluster states.For materials near the phase boundary between weak and strong topological insulators (TIs), their band topology depends on the band alignment, with the inverted (normal) band corresponding to the strong (weak) TI phase. Here, taking the anisotropic transition-metal pentatelluride ZrTe_5 as an example, we show that the band inversion manifests itself as a second extremum (band gap) in the layer stacking direction, which can be probed experimentally via magnetoinfrared spectroscopy. Specifically, we find that the band anisotropy of ZrTe_5 features a slow dispersion in the layer stacking direction, along with an additional set of optical transitions from a band gap next to the Brillouin zone center. Our work identifies ZrTe_5 as a strong TI at liquid helium temperature and provides a new perspective in determining band inversion in layered topological materials.We propose a new mechanism to generate the Casimir-Lifshitz torque between Weyl semimetals arising from the chiral anomaly. For short distances ranging from a nanometer to a few tens of nanometers, chiral anomaly is manifested via a Casimir-Lifshitz torque ∼sin(θ) with θ being the twisting angle. As the distance between Weyl semimetals increases from a submicrometer to a few micrometers, chiral-anomaly-driven Casimir-Lifshitz torque between Weyl semimetals is remarkably large, which is comparable with that of conventional birefringent materials.We present all-multiplicity formulas for the tree-level scattering of gluons and gravitons in the maximal helicity violating (MHV) helicity configuration, calculated in certain chiral strong fields. The strong backgrounds we consider are self-dual plane waves in gauge theory and general relativity, which are treated exactly and admit a well-defined S matrix. The gauge theory background-coupled MHV amplitude is simply a dressed analog of the familiar Parke-Taylor formula, but the gravitational version has nontrivial new structures due to graviton tails. Both formulas have just one residual integral rather than the n-2 expected at n points from space-time perturbation theory; this simplification arises from the integrability of self-dual backgrounds and their corresponding twistor description. The resulting formulas pass several consistency checks and limit to the well-known expressions for MHV scattering of gluons and gravitons when the background becomes trivial.Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.We demonstrate formation of the ideal split-vacancy configuration of the Sn-vacancy center upon implantation into natural diamond. Atuveciclib order Using β^- emission channeling following low fluence ^121Sn implantation (2×10^12  atoms/cm^2, 60 keV) at the ISOLDE facility at CERN, we directly identified and quantified the atomic configurations of the Sn-related centers. Our data show that the split-vacancy configuration is formed immediately upon implantation with a surprisingly high efficiency of ≈40%. Upon thermal annealing at 920 °C ≈30% of Sn is found in the ideal bond-center position. Photoluminescence revealed the characteristic SnV^- line at 621 nm, with an extraordinarily narrow ensemble linewidth (2.3 nm) of near-perfect Lorentzian shape. These findings further establish the SnV^- center as a promising candidate for single photon emission applications, since, in addition to exceptional optical properties, it also shows a remarkably simple structural formation mechanism.We study the connection between the charging power of quantum batteries and the fluctuations of the extractable work. We prove that in order to have a nonzero rate of change of the extractable work, the state ρ_W of the battery cannot be an eigenstate of a "free energy operator," defined by F≡H_W+β^-1log(ρ_W), where H_W is the Hamiltonian of the battery and β is the inverse temperature of a reference thermal bath with respect to which the extractable work is calculated. We do so by proving that fluctuations in the free energy operator upper bound the charging power of a quantum battery. Our findings also suggest that quantum coherence in the battery enhances the charging process, which we illustrate on a toy model of a heat engine.We study the exchange interactions and resulting magnetic phases in the honeycomb cobaltates. For a broad range of trigonal crystal fields acting on Co^2+ ions, the low-energy pseudospin-1/2 Hamiltonian is dominated by bond-dependent Ising couplings that constitute the Kitaev model. The non-Kitaev terms nearly vanish at small values of trigonal field Δ, resulting in spin liquid ground state. Considering Na_3Co_2SbO_6 as an example, we find that this compound is proximate to a Kitaev spin liquid phase, and can be driven into it by slightly reducing Δ by ∼20  meV, e.g., via strain or pressure control. We argue that, due to the more localized nature of the magnetic electrons in 3d compounds, cobaltates offer the most promising search area for Kitaev model physics.