Long-range inverse two-spin correlations in one-dimensional Potts lattices

The inverse two-spin correlation function of a one-dimensional three-state Potts lattice with constant nearest-neighbor interactions in a uniform external field is derived exactly. It is shown that the external field induces long-range correlations. The inverse two-spin correlation function decays in a monotonie exponential fashion for a ferromagnetic lattice, while it decays in an oscillatory exponential fashion for an antiferromagnetic lattice. With no external field the inverse two-spin correlation function has a finite range equal to that of the interactions.     

Long-range electron binding to quadrupolar molecules

An excess electron can be bound to a molecule in a very diffuse orbital as a result of the long-range contributions of the molecular electrostatic field. Following a systematic search, we report experimental evidence that quadrupole binding occurs for the trans-succinonitrile molecule (EA=20+/-2 meV), while the gauche-succinonitrile conformer supports a dipole-bound anion state (EA=108+/-10 meV). Theoretical calculations at the DFT/B3LYP level support these interpretations and give electron affinities of 20 and 138 meV, respectively.     

Long-range influence of weak optical irradiation of silicon

We report a new effect, observed experimentally in silicon under irradiation with visible-range light with a power density of 0.2–1.5 W/cm² for 8 s. The effect consists in an increase of microhardness on the side opposite to the irradiated side and is not purely thermal in character. After irradiation, the changes decrease exponentially with time with an activation energy of 0.75±0.05 eV, a value which is characteristic for the migration and reorientation of one of the types of intrinsic interstitial atoms. A qualitative explanation is given for the effect on the basis of a model previously proposed for the case of long-range influence of ion irradiation. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 6, 381–385 (25 September 1999)     

Tunable optical properties in engineered one-dimensional coupled resonator optical waveguides

In this paper, the optical properties in finite size tilted and engineered one dimensional coupled resonator optical waveguide have been investigated. The large dependence of the optical transmittance, dispersion parameter and its higher order slope such as transmittance group delay, third order dispersion and intrinsic waveguide induced loss on the oblique incidence and fraction factor, as the ratio of the optical thicknesses of two adjacent layers, have been studied. Our results showed that as a consequence of changing the fraction factor, at normal incidence, photonic band gap zone, flat portion of third order dispersion curve and maximum magnitude of the transmission group delay can be tuned in long range of wavelength (red shift) slightly. Despite of slight tuning the optical properties in one dimensional coupled resonator optical waveguide by changing the fraction factor, incidence angle has a significant large magnitude of tunability in the overall region of operational wavelength. This fact yields us by changing the incidence from 30 to 60, the operational wavelength can be tuned between two main optical communication windows, while by changing the fraction factor, dispersion and its higher order can be fine tuned in each of optical communication windows which are very useful in wavelength division multiplexing systems and planar lightwave circuits.     

Vortex-lattice melting in a one-dimensional optical lattice

We investigate quantum fluctuations of a vortex lattice in a one-dimensional optical lattice for realistic numbers of particles and vortices. Our method gives full access to all the modes of the vortex lattice and we discuss in particular the Bloch bands of the Tkachenko modes. Because of the small number of particles in the pancake Bose-Einstein condensates at every site of the optical lattice, finite-size effects become very important. Therefore, the fluctuations in the vortex positions are inhomogeneous and the melting of the lattice occurs from the outside inwards. By looking into correlations between neighboring vortices, we identify new solid and liquid phases. Tunneling between neighboring pancakes substantially reduces the inhomogeneity as well as the size of the fluctuations.     

Quantum computation with a one-dimensional optical lattice

We present an economical dynamical control scheme to perform quantum computation on a one-dimensional optical lattice, where each atom encodes one qubit. The model is based on atom tunneling transitions between neighboring sites of the lattice. They can be activated by external laser beams resulting in a two-qubit phase gate or in an exchange interaction. A realization of the Toffoli gate is presented, which requires only a single laser pulse and no individual atom addressing.     

Long-range optical fibre backscatter loss signatures using t wo-point processing

The ability of the two-point technique to obtain accurate backscatter loss signatures for fibre systems with long repeater spacing is investigated. A systematic analysis of the attenuation range capability of two-point processing is presented and a predicted measurement range of 40 dB one-way fibre attenuation verified by measurement. The analysis takes into account the effect of receiver bandwidth, quantization noise and A–D converter nonlinearity.     

Higher-order surface solitons in one-dimensional Bessel optical lattices

We demonstrate the existence of higher-order solitons occurring at an interface separating two one-dimensional (1D) Bessel optical lattices with different orders or modulation depths in a defocusing medium. We show that, in contrast to homogeneous waveguides where higher-order solitons are always unstable, the Bessel lattices with an interface support branches of higher-order structures bifurcating from the corresponding linear modes. The profiles of solitons depend remarkably on the lattice parameters and the stability can be enhanced by increasing the lattice depth and selecting higher-order lattices. We also reveal that the interface model with defocusing saturable Kerr nonlinearity can support stable multi-peaked solitons. The uncovered phenomena may open a new way for soliton control and manipulation.     

Off-site trimer superfluid on a one-dimensional optical lattice

The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional(1D) lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601(R)(2010)]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.     

Transverse optical mode in a one-dimensional Yukawa chain

A transverse optical mode was observed in a one-dimensional Yukawa chain. Charged particles, suspended in a strongly coupled dusty plasma, were arranged in a 1D periodic structure. Particle displacement in the direction perpendicular to the chain was restored by the confining potential. The dispersion relation of phonons was measured, verifying that the optical mode has negative dispersion, with phase and group velocities that are oppositely directed. A theoretical dispersion relation is presented and compared to the experiment and a molecular dynamics simulation.     

Long-range simplex-coded BOTDA sensor over 120 km distance employing optical preamplification

In this Letter, we combine the use of optical preamplification at the receiver and optical pulse coding techniques with an optimized modulation format to effectively extend the sensing range of Brillouin optical time-domain analysis (BOTDA) sensors. Combining a return-to-zero modulation format with 25% duty cycle and linear gain preamplification allows for temperature and strain measurements over 120 km of standard single-mode fiber with 3 m spatial resolution and an rms strain-temperature accuracy of 3.1 °C/60 με respectively.     

Long-range propagation of plasmon polaritons in a thin metal film on a one-dimensional photonic crystal surface

We present experimental results on ultralong-range surface plasmon polaritons, propagating in a thin metal film on a one-dimensional (1D) photonic crystal surface over a distance of several millimeters. This propagation length is about 2 orders of magnitude higher than the one in the ordinary Kretschmann configuration at the same optical frequency. We show that a long-range surface plasmon polaritons propagation may take place not only in a (quasi)symmetrical scheme, where a thin metal film is located between two media with (approximately) the same refraction index, but also in a scheme where the thin metal film is located between an appropriate 1D photonic crystal and an arbitrary (air, water, etc.) medium. The ultralong-range surface plasmon polaritons are potentially important for biosensors, plasmonics, and other applications.     

Guiding of a one-dimensional optical beam with nanometer diameter

The concept of a one-dimensional optical wave and its waveguides are proposed for what is to our knowledge the first time. The proposed waveguides are principally new and named for one-dimensional optical waveguides. One-dimensional optical waveguides make it possible to guide very thin optical beams in the visible or the near-infrared region with a diameter in the nanometer range. The propagation properties are analyzed theoretically. The applications of the waveguides to optical devices in the nanometer range are discussed.     

Enhanced nonlinear optical response of one-dimensional metal-dielectric photonic crystals

We describe a new type of artificial nonlinear optical material composed of a one-dimensional metal-dielectric photonic crystal. Because of the resonant nature of multiple Bragg reflections, the transmission within the transmission band can be quite large, even though the transmission through the same total thickness of bulk metal would be very small. This procedure allows light to penetrate into the highly nonlinear metallic layers, leading to a large nonlinear optical response. We present experimental results for a Cu/SiO(2) crystal which displays a strongly enhanced nonlinear optical response (up to 12X) in transmission.     

Convective boson-fermion pairing mode in one-dimensional oscillating optical superlattice

A convective pairing mode of a boson-fermion mixture of ultracold atoms confined in an optical superlattice can be induced by the transformation between two optical superlattice configurations. This convective pairing mode only exists in discrete momentum vector zones for pairing energy gaps. The energy spectrum of gapped states is characterized by topological winding numbers. Two neighboring gapped states are bridged by an unstable chiral linear mode, which drives the boson-fermion pair into directional motion for a short period but remains static in the supersymmetric phase with time-reversal symmetry. The phase transition from a gapped mode to a gapless mode occurs at a critical temperature, whose distribution curve for chemical potential demonstrates a similar dome-like trend as that of high $T_c$ superconductor. The boson-fermion pairing may shed light on a possible mechanism of high-$T_c$ superconductivity.     

Phase diagram of Bose-Fermi mixtures in one-dimensional optical lattices

The ground state phase diagram of the one-dimensional Bose-Fermi Hubbard model is studied in the canonical ensemble using a quantum Monte Carlo method. We focus on the case where both species have half filling in order to maximize the pairing correlations between the bosons and the fermions. In case of equal hopping we distinguish among phase separation, a Luttinger liquid phase, and a phase characterized by strong singlet pairing between the species. True long-range density waves exist with unequal hopping amplitudes.     

Surface solitons supported by one-dimensional composite Bessel optical lattices

We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional （1D） composite Bessel optical lattice. This setting is composed of two Bessel lattices with different orders and different modulation depths, separated beside both sides of an interface. Stability analysis and numerical propagation simulations prove that solitons supported by the model are dynamically stable in the entire domain of their existence. The order of lattice determines the shape of soliton, and the amplitude of soliton depends on the lattice modulation depth. The experimental realization of the scheme is also proposed. Our results may provide another effective way of controlling the shapes of surface solitons and thus their evolutions by introducing a new freedom degree.     

Superfluid to Mott-insulator transition in a one-dimensional optical lattice

Bose-Einstein condensates (BEC) of sodium atoms are transferred into one-dimensional (1D) optical lattice potentials, formed by two laser beams with a wavelength of 1064 nm, in a shallow optical trap. The phase coherence of the condensate in the lattice potential is studied by changing the lattice depth. A qualitative change in behavior of the BEC is observed at a lattice depth of ～ 13.7 E_r, where the quantum gas undergoes a transition from a superfluid state to a state that lacks well-to-well phase coherence.