d-Dimensional quantum secret sharing without entanglement

A d-dimensional quantum state secret sharing scheme without entanglement is proposed. In the proposed scheme, the dealer generates a single quantum state in d-dimensional Hilbert space, and performs the Pauli unitary operation on the quantum state according to the private keys of the participants. In the recovery phase, each participant performs the Pauli operation on the quantum state according to his private key, and the last participant will recover the original quantum state. Compared to the existing quantum secret sharing schemes, the main contribution of the proposed scheme is that the quantum state can be shared without the entanglement, so the sharing of the quantum state is more practical.     

Nuclear spin-lattice relaxation rate in Kondo superconductors in the gapless state

The host nuclear spin-lattice relaxation rates in Kondo superconductors in the gapless state are derived within the framework of the Matsuura, Ichinose, and Nagaoka (MIN) theory of the Kondo effect. The relaxation rates for both low-T _K and high-T _K Kondo superconductors are obtained. The temperature dependence of the relaxation rate in low-T _K Kondo superconductors in the gapless state arising from the pair breaking by the Kondo impurity is obtained. The dependence of the relaxation rate for high-T _K Kondo superconductors in the gapless state on the external magnetic field producing the gapless state is also obtained.     

A Compact Treatment of Singular Impurities Using the Artificial Friedel Resonance (FAIR) Technique

Building on the tools that Friedel introduced in the 1950s, an off-spring of the Friedel resonance is developed, which is called the FAIR approach for “Friedel Artificially Inserted Resonance”. In the FAIR approach, an arbitrary s-electron state a₀^fa_{0}^{\dagger} is cut out of the conduction band, and the remaining free electron Hamiltonian is orthogonalized, yielding an artificial Friedel resonance. In the presence of a real Friedel d-resonance state d ^†, one can find an optimal fair state a₀^fa_{0}^{\dagger} so that the exact n-electron ground state consists of two Slater states, one containing the d-electron and the other the fair state a₀^fa_{0}^{\dagger}. This separation according to the d-occupation is ideal for impurities with a Coulomb interaction between d-electrons. The wave function of the Friedel–Anderson (FA) impurity in the magnetic state and the singlet state are constructed with the FAIR method using two fair states a₀^fa_{0}^{\dagger} and b₀^fb_{0}^{\dagger}. The magnetic state consists of four, and the singlet state consists of eight Slater states. The latter is invariant with respect to the inversion of all spins. The FAIR ground state Ψ _SS for the singlet state is composed of two magnetic states Ψ _MS with opposite moments which are not orthogonal to each other. The degree of overlap determines the Kondo energy. Because of the compactness of the wave function, a number of properties can be calculated relatively quickly. Comparison with the best previous ground state energy and d-occupation by Gunnarson and Schoenhammer show excellent agreement. A number of physical properties are calculated; among them are (i) the Kondo cloud in a small magnetic field. Two components of polarization are observed (in linear response), an oscillating part and a nonoscillating part. (ii) The fidelity which represents the scalar product between the ground states of the symmetric FA-impurity and the symmetric Friedel impurity is calculated as a function of the number of electron states. (In the literature, this has the somewhat misleading name of fidelity.) This calculation does not show an Anderson orthogonality catastrophe, which indicates that the FA ground state has a phase shift of π/2 at the Fermi energy. (iii) The Friedel oscillations of the FA-impurity. Surprisingly, these oscillations are very similar to the Friedel oscillations of a very narrow Friedel resonance at the Fermi level. The amplitude A(r) is close to zero at short distances and saturates at two for large distances. The inversion point where A(r)=1 correlates with the characteristic energies of the impurities, the half-band width Γ for the Friedel impurity and the Kondo energy for the FA-impurity. This raises the fascinating question how these simple properties are hidden in the multielectron wave function.     

Kinetics of swelling/shrinking rearrangement of a self-aggregated nanohydrogel at solid/liquid interfaces

The hydrogel nanoparticles (nanohydrogels) have great potentials in numerous biomedical applications. Biomembrane-mimetic self-assemble nanohydrogel MC _n (n repeated 2-methacryloyloyloxyethyl phosphoryl choline grafted cholesteryl group-bearing pullulan) was designed. In order to mimic the interfacial responses of fibrinogen at the hydrophobic/hydrophilic surfaces, MC _n molecules were controlled by the chain length of the decorated MPC in term(s) of n?=?0, 6.2, 14.3 and 180, respectively. The dynamic rearrangements of MC _n hydrogel molecular layer on the hydrophobic highly ordered pyrolytic graphite surface were observed by the atomic force microscopy. The results showed that there were biphasic transitions at the liquid/solid interfaces from the initial solute state to metastable state to the equilibrium state. The length of MPC branches, n, governed the changes of layer thickness to the equilibrium state appearing as swelling or shrinking. The time evolution of the thickness was fitted by a single exponential model, and the kinetics parameters of surface rearrangements to the equilibrium state were obtained.     

Generalized remote preparation of the d -level N -particle GHZ state

With one pair of entangled particles as the quantum channel, we present an explicit generalized protocol for preparing remotely a two-level N-particle Greenberger–Horne–Zeilinger (GHZ) state and generalize it to the d-level case. We show that by properly choosing the measurement basis it is possible to achieve unity fidelity remote preparation of the state. This protocol has the advantage of transmitting much fewer particles for remote preparation of the d-level N-particle GHZ state.     

Superconductivity and Pseudogap States in λ-(BEDT-TSF)2GaCl4 : Microwave Conductivity Measurements

We have investigated the 45 GHz microwave response from an organic superconductor λ-(BEDT-TSF)₂GaCl₄ with T _c = 4.8 K. In the superconducting state, the London penetration depth saturates well below T _c , which may provide an evidence for a conventional s-wave paring. In the metallic state, σ₁ ^c deviates downward from σ _dc ^c , while σ₂ ^c , which should be zero in a conventional metallic state, increases exponentially toward T _c . This anomalous metallic state has been discussed in terms of a possible formation of incoherent electron pairs in so-called a pseudogap state.     

Normal State Resistivity of Underdoped YBa2Cu3Ox Thin Films and La2-xSrxCuO4 Ultra-Thin Films under Epitaxial Strain

The normal state resistivity of high temperature superconductors can be probed in the region below T _c by suppressing the superconducting state in high magnetic fields. Here we present the normal state properties of YBa ₂ Cu ₃ O _x thin films in the underdoped regime and the normal state resistance of La _2-x Sr _x CuO ₄ thin films under epitaxial strain, measured below T _c by applying pulsed fields up to 60 T. We interpret these data in terms of the recently proposed 1D quantum transport model with the 1D paths corresponding to the charge stripes.     

Superfluid turbulence in a nonuniform circular channel

We have measured the dissipation associated with superfluid turbulence in a nonuniform channel of circular cross section in order to further explore the discrepancies with theory discovered previously in a nonuniform rectangular channels. Our data show that the two turbulent states supported in uniform circular channels (TI andTII) are also present in our experiments for either diverging or converging flow, indicating that this two-state structure is quite robust. The transition from laminar flow to theTI state and the transition from theTI to theTII state each occur at stationary turbulent fronts in the channel. One consequence of this phenomenon is that theTI/TII transition is substantially broadened. Our data for theTI state, when analysed assuming local uniformity, are in excellent agreement with previous results from uniform channels. The broadenedTI/TII transition severely restricts our experimental access to theTII state. Nevertheless, our data are consistent with the same kind of modification to the vortex line density found for the nonuniform rectangular channels.     

Spin singlet-triplet states of superfluid Fermi liquids in the presence of strong magnetic fields

The unitary singlet-triplet states of superfluid Fermi liquids are investigated in the presence of strong magnetic fields. The static spin susceptibility is calculated in the limith 0 in the framework of the weak coupling approximation. It is predicted that BS (a mixture of the Balian- Werthamer anisotropic state andD-wave singlet state) and 2DS (a mixture of the planar 2D state andD-wave singlet state) spin singlet-triplet states become stable at some temperatures and magnetic fields.     

Quantum teleportation with a complete Bell state measurement

By using the quantum teleportation protocol, Alice can send an unknown quantum state (e.g. the polarization of a single photon) to Bob without ever knowing about it. This paper discusses a quantum teleportation experiment in which nonlinear interactions are used for the Bell state measurement. Since the Bell state measurement is based on nonlinear interactions, all four Bell states can be distinguished. Therefore, teleportation of a polarization state can occur with certainty, in principle. Details of the theory and the experimental set-up are discussed.     

Effects of lanthanum modification on dielectric properties of Pb(Zr<Subscript>0.90</Subscript>,Ti<Subscript>0.10</Subscript>)O<Subscript>3</Subscript> ceramics: enhanced antiferroelectric stability

Lanthanum modified lead zirconate titanate ceramics with lanthanum content changing from 2 to 6 at% La and a Zr/Ti ratio of 90/10 (PLZT x/90/10) have been analyzed by using X-ray diffraction, dielectric response, differential scanning calorimetry, and ferroelectric hysteresis. An antiferroelectric state was found to be stabilized, whereas the long-range ferroelectric state was disrupted by lanthanum substitution on the lead sites. A ferroelectric state is shown to be stable over an antiferroelectric state for low lanthanum contents in a wide temperature range, where both phases coexist. With the increase of the lanthanum concentration, the long-range coherency of the ferroelectric state is suppressed, i.e., the temperature range of the ferroelectric state stability decreased, disappearing for x > 3 at% La.     

Effects of Higher Hopping Terms on the Stripe States in the Two-Dimensional Hubbard Model

Using the variational Monte Carlo method for the two-dimensional t-t′-t″-U Hubbard model, we discuss the ground state of the underdoped region on the high-T _c cuprates. We found that, while stripe states with the periodicity consistent with experiments for La_{2− x} Sr _x CuO₄ are stabilized in the case of t′/t < 0, the positive t′/t makes the stripe state unstable with the lowest energy state being the commensurate AF state, which is consistent with experiments on the electron doping system such as Nd_{2− x} Ce _x CuO₄. We also show that the stripe state is sensitive to the value of t″/t > 0. These results indicate that the nesting condition is a critical factor to the stripe instability.     

Nuclear relaxation in the superconducting state of (MDT-TTF)2AuI2

We report the results of our attempt to measure the proton nuclear relaxation rate, 1/T ₁, in the superconducting state of the title material. The relaxation rate in the superconducting state at a field of 1 T was found much longer than that in the normal state, but it became clear that the dominant contribution came from the normal core region. The nuclear relaxation at zero field was examined by using the field cycling technique. An ln(t) term in the relaxation curve was observed at low temperatures, suggesting the contribution of the creeping motion of vortices. We discuss the possibility to determine the intrinsic temperature dependence of 1/T ₁ in the superconducting state.     

Influence of the state of the lattice on the pair breaking of manganese in superconducting cadmium

The superconducting transition temperature of crystalline and amorphous cadmium doped with dilute Mn atoms was measured. In the first case the initial depression ofT _c as function of concentration isdT _c /dc=5.4 K/at % and in the second casedT _c /dc=2.65 K/at %. Both systems show non linear behavior at higher concentrations, the one in the crystalline state much more than the one in the amorphous state. While the curve in the amorphous state fits the Abrikosov-Gor'kov theory to the experimental limit of 70 mK, i.e., to within 3% of the critical concentration, the curve in the crystalline state does not, but is interpretable with the Müller-Hartmann-Zittartz theory with a Kondo temperature of10 ^–6 K.Supported by the Deutsche Forschungsgemeinschaft in the Sonderforschungsbereich 125, Fehlordnung in Metallen Aachen, Jülich, Köln.     

Virial equation of state and ideal-gas heat capacities of pentafluoro-dimethyl ether

A virial equation of state is presented for vapor-phase pentafluoro-dimethyl ether (CF₃−O−CF₂H), a candidate alternative refrigerant known as E125. The equation of state was determined from density measurements performed with a Burnett apparatus and from speed-of-sound measurements performed with an acoustical resonator. The speed-of-sound measurements spanned the ranges 260≤T≤400 K and 0.05≤P≤1.0 MPa. The Burnett measurements covered the ranges 283≤T≤373 K and 0.25≤P≤5.0 MPa. The speed-of-sound and Burnett measurements were first analyzed separately to produce two independent virial equations of state. The equation of state from the acoustical measurements reproduced the experimental sound speeds with a fractional RMS deviation of 0.0013%. The equation of state from the Burnett measurements reproduced the experimental pressures with a fractional RMS deviation of 0.012%. Finally, an equation of state was fit to both the speed-of-sound and the Burnett measurements simultaneously. The resulting equation of state reproduced the measured sound speeds with a fractional RMS deviation of 0.0018% and the measured Burnett densities with a fractional RMS deviation of 0.019%.     

Models for Third Sound in Thin 3He-4He Films

Third sound speeds in ³ He- ⁴ He thin films are sensitive to the transverse single-particle state occupied by the ³ He. The third sound speed in the low coverage region with the ³ He occupying the transverse ground-state can be understood quantitatively. The onset of occupation of the first excited transverse state is signaled by a high coverage feature in the third sound speed. Three third sound models for the high coverage region, differing in their assumptions about the spatial distribution of the excited states, are introduced. Using the experimental third sound data, these models can also be used to infer the fractional population of the ³ He in the first excited state as a function of coverage. It is found that the third sound analyses each predict a larger fractional population in the first excited state at monolayer completion than a recent analysis of magnetization step data taken on the same system.     

An Analytical Equation of State for Alkaline Earth Metals

In this work, an analytical equation of state based on statistical mechanical perturbation theory, which was initially developed for normal fluids and can be applied to predict the P–V–T data for saturated liquid alkaline earth metals, is presented. The equation of state is that of Ihm, Song, and Mason, and the temperature-dependent parameters of the equation of state are calculated from a corresponding-states correlation as functions of the reduced temperature. Two scaling constants are sufficient for this purpose, the surface tension and the liquid density at the melting point. The equation of state is used to predict the saturated liquid density of molten alkaline earth metals from the melting point up to 2000 K, for which experimental data exist, within an accuracy of 5%.     

Dynamics of deviations from the Gaussian state in a freely cooling homogeneous system of smooth inelastic particles

The time dependence of deviations from the Gaussian state in a freely cooling homogeneous system of smooth inelastically colliding spheres is investigated by kinetic theory. We determine the full time dependence of the coefficients of an expansion around the Gaussian state in Generalized Laguerre polynomials. Approximating this system of equations to sixth order, we find that the asymptotic state, where the mean energy T follows Haff's law with time independent cooling rate, is reached within a few collisions per particle. Two-dimensional molecular dynamics simulations confirm our results and show exponential behavior in the high-energy tails. Received: 10 January 2000     

Equations of State for Technical Applications. II. Results for Nonpolar Fluids

New functional forms have been developed for multiparameter equations of state for non- and weakly polar fluids and for polar fluids. The resulting functional forms, which were established with an optimization algorithm which considers data sets for different fluids simultaneously, are suitable as a basis for equations of state for a broad variety of fluids. The functional forms were designed to fulfill typical demands of advanced technical applications with regard to the achieved accuracy. They are numerically very stable and their substance-specific coefficients can easily be fitted to restricted data sets. In this way, a fast extension of the group of fluids for which accurate empirical equations of state are available becomes possible. This article deals with the results found for the non- and weakly polar fluids methane, ethane, propane, isobutane, n-butane, n-pentane, n-hexane, n-heptane, n-octane, argon, oxygen, nitrogen, ethylene, cyclohexane, and sulfur hexafluoride. The substance-specific parameters of the new equations of state are given as well as statistical and graphical comparisons with experimental data. General features of the new class of equations of state such as their extrapolation behavior and their numerical stability have been discussed in a preceding article. Results for typical polar fluids will be discussed in a subsequent article.     

Multimode polarization degree of mixture optical states in integrated directional couplers

Mixture multimode optical field classical states propagating in N?×?N integrated directional couplers are analyzed by using the density matrix formalism in a N-dimensional optical space. These mutimode optical fields present a kind of generalized polarization and accordingly a definition of a multimode polarization degree is proposed. It is based on the distance measure between a mixture state and an unpolarized state in a N-dimensional optical space so that in the case N=2 the standard polarization degree is recovered. It is shown that directional couplers can reduce or increase remarkably the multimode polarization degree of a mixture state. Likewise a simple measurement technique, based on Y junctions, of this multimode polarization degree is proposed. Finally all the results can be formally extended to the special case of multimode single photon quantum states.