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Quantum teleportation and information splitting via four-qubit cluster state and a Bell state
Marlon David González Ramírez, Babatunde James Falaye, Guo-Hua Sun, M. Cruz-Irisson, Shi-Hai Dong
Front. Phys. . 2017, 12 (5 ): 120306-.
https://doi.org/10.1007/s11467-017-0684-8
Quantum teleportation provides a “bodiless” way of transmitting the quantum state from one object to another, at a distant location, using a classical communication channel and a previously shared entangled state. In this paper, we present a tripartite scheme for probabilistic teleportation of an arbitrary single qubit state, without losing the information of the state being teleported, via a fourqubit cluster state of the form |φ 〉1234 =α |0000〉+β |1010〉+γ |1010〉-η |1010〉, as the quantum channel, where the nonzero real numbers α , β , γ , and η satisfy the relation |α |2 +|β |2 +|γ |2 +|η |2 =1. With the introduction of an auxiliary qubit with state |0〉, using a suitable unitary transformation and a positive-operator valued measure (POVM), the receiver can recreate the state of the original qubit. An important advantage of the teleportation scheme demonstrated here is that, if the teleportation fails, it can be repeated without teleporting copies of the unknown quantum state, if the concerned parties share another pair of entangled qubit. We also present a protocol for quantum information splitting of an arbitrary two-particle system via the aforementioned cluster state and a Bell-state as the quantum channel. Problems related to security attacks were examined for both the cases and it was found that this protocol is secure. This protocol is highly efficient and easy to implement.
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Entanglement of coherent superposition of photon-subtraction squeezed vacuum
Cun-Jin Liu, Wei Ye, Wei-Dong Zhou, Hao-Liang Zhang, Jie-Hui Huang, Li-Yun Hu
Front. Phys. . 2017, 12 (5 ): 120307-.
https://doi.org/10.1007/s11467-017-0694-6
A new kind of non-Gaussian quantum state is introduced by applying nonlocal coherent superposition (τa + sb )m of photon subtraction to two single-mode squeezed vacuum states, and the properties of entanglement are investigated according to the degree of entanglement and the average fidelity of quantum teleportation. The state can be seen as a single-variable Hermitian polynomial excited squeezed vacuum state, and its normalization factor is related to the Legendre polynomial. It is shown that, for τ =s , the maximum fidelity can be achieved, even over the classical limit (1/2), only for evenorder operation m and equivalent squeezing parameters in a certain region. However, the maximum entanglement can be achieved for squeezing parameters with a π phase difference. These indicate that the optimal realizations of fidelity and entanglement could be different from one another. In addition, the parameter τ /s has an obvious effect on entanglement and fidelity.
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Dynamical phase transitions in a two-species bosonic Josephson junction
Jing Tian, Jun Liu, Hai-Bo Qiu, Xiao-Qiang Xi
Front. Phys. . 2017, 12 (5 ): 120509-.
https://doi.org/10.1007/s11467-017-0687-5
We investigate dynamical phase transitions that are induced by interspecies interaction in a two-species bosonic Josephson junctions (BJJ), based on semi-classical theory. In zero-phase mode, similar to the case of a single-species BJJ, we observe the well-known dynamical phase transition from Josephson oscillation to self-trapping, which can be induced by both enhanced repulsive and attractive interspecies interactions. In π phase mode, dynamical phase transitions are even more interesting and counterintuitive. We characterize a dynamical phase transition with the merging of two separate phase space domains into one, which is induced by increasing repulsive interspecies interaction. On the other hand, we find that by increasing attractive interspecies interaction, a phase separation of two formally overlapped phase space domains will occur. At last, we reveal that these intriguing dynamical phase transitions are caused by different kinds of bifurcations.
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Prospects for rare and forbidden hyperon decays at BESIII
Hai-Bo Li
Front. Phys. . 2017, 12 (5 ): 121301-.
https://doi.org/10.1007/s11467-017-0691-9
The study of hyperon decays at the Beijing Electron Spectrometer III (BESIII) is proposed to investigate the events of J /φ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron–Positron Collider II. About 106 –108 hyperons, i.e., ? , Σ ,Ξ and Ω , will be produced in the J /φ and φ (2S ) decays with the proposed data samples at BESIII. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of 10-5 –10-8 . In addition, with the known center-of-mass energy and “tag technique”, rare decays and decays with invisible final states can be probed.
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Isolated structures in two-dimensional optical superlattice
Xin-Hao Zou,Bao-Guo Yang,Xia Xu,Peng-Ju Tang,Xiao-Ji Zhou
Front. Phys. . 2017, 12 (5 ): 123201-.
https://doi.org/10.1007/s11467-016-0626-x
Overlaying commensurate optical lattices with various configurations called superlattices can lead to exotic lattice topologies and, in turn, a discovery of novel physics. In this study, by overlapping the maxima of lattices, a new isolated structure is created, while the interference of minima can generate various “sublattice” patterns. Three different kinds of primitive lattices are used to demonstrate isolated square, triangular, and hexagonal “sublattice” structures in a two-dimensional optical superlattice, the patterns of which can be manipulated dynamically by tuning the polarization, frequency, and intensity of laser beams. In addition, we propose the method of altering the relative phase to adjust the tunneling amplitudes in “sublattices”. Our configurations provide unique opportunities to study particle entanglement in “lattices” formed by intersecting wells and to implement special quantum logic gates in exotic lattice geometries.
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Cross-symmetry breaking of two-component discrete dipolar matter-wave solitons
Yong-Yao Li, Zhi-Wei Fan, Zhi-Huan Luo, Yan Liu, He-Xiang He, Jian-Tao Lü, Jia-Ning Xie, Chun-Qing Huang, Hai-Shu Tan
Front. Phys. . 2017, 12 (5 ): 124206-.
https://doi.org/10.1007/s11467-017-0702-x
We study the spontaneous symmetry breaking of dipolar Bose–Einstein condensates trapped in stacks of two-well systems, which may be effectively built as one-dimensional trapping lattices sliced by a repelling laser sheet. If the potential wells are sufficiently deep, the system is modeled by coupled discrete Gross–Pitaevskii equations with nonlocal self- and cross-interaction terms representing dipole–dipole interactions. When the dipoles are not polarized perpendicular or parallel to the lattice, the crossinteraction is asymmetric, replacing the familiar symmetric two-component solitons with a new species of cross-symmetric or-asymmetric ones. The orientation of the dipole moments and the interwell hopping rate strongly affect the shapes of the discrete two-component solitons as well as the characteristics of the cross-symmetry breaking and the associated phase transition. The sub- and super-critical types of cross-symmetry breaking can be controlled by either the hopping rate between the components or the total norm of the solitons. The effect of the interplay between the contact nonlinearity and the dipole angle on the cross-symmetry breaking is also discussed.
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Fulde–Ferrell–Larkin–Ovchinnikov pairing states between s - and p -orbital fermions
Shu-Yang Wang, Jing-Wei Jiang, Yue-Ran Shi, Qiongyi He, Qihuang Gong, Wei Zhang
Front. Phys. . 2017, 12 (5 ): 126701-.
https://doi.org/10.1007/s11467-017-0681-y
We study the pairing states in a largely imbalanced two-component Fermi gas loaded in an anisotropic two-dimensional optical lattice, where the spin-up and spin-down fermions are filled to the s - and p x -orbital bands, respectively. We show that owing to the relative inversion of the band structures of the s and p x orbitals, the system favors pairing between two fermions on the same side of the Brillouin zone, leading to a large stable regime for states with a finite center-of-mass momentum, i.e., the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state. In particular, when two Fermi surfaces are close in momentum space, a nesting effect stabilizes a special type of π -FFLO phase with a spatial modulation of π along the easily tunneled x direction. We map out the zero-temperature phase diagrams within the mean-field approach for various aspect ratios within the two-dimensional plane and calculate the Berezinskii–Kosterlitz–Thouless (BKT) transition temperatures T BKT for different phases.
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Superfluid response in heavy fermion superconductors
Yin Zhong,Lan Zhang,Can Shao,Hong-Gang Luo
Front. Phys. . 2017, 12 (5 ): 127101-.
https://doi.org/10.1007/s11467-016-0625-y
Motivated by a recent London penetration depth measurement [H. Kim, et al., Phys. Rev. Lett . 114, 027003 (2015)] and novel composite pairing scenario [O. Erten, R. Flint, and P. Coleman, Phys. Rev. Lett . 114, 027002 (2015)] of the Yb-doped heavy fermion superconductor CeCoIn5 , we revisit the issue of superfluid response in the microscopic heavy fermion lattice model. However, from the literature, an explicit expression for the superfluid response function in heavy fermion superconductors is rare. In this paper, we investigate the superfluid density response function in the celebrated Kondo–Heisenberg model. To be specific, we derive the corresponding formalism from an effective fermionic large-N mean-field pairing Hamiltonian whose pairing interaction is assumed to originate from the effective local antiferromagnetic exchange interaction. Interestingly, we find that the physically correct, temperature-dependent superfluid density formula can only be obtained if the external electromagnetic field is directly coupled to the heavy fermion quasi-particle rather than the bare conduction electron or local moment. Such a unique feature emphasizes the key role of the Kondo-screening-renormalized heavy quasi-particle for low-temperature/energy thermodynamics and transport behaviors. As an important application, the theoretical result is compared to an experimental measurement in heavy fermion superconductors CeCoIn5 and Yb-doped Ce1−x Ybx CoIn5 with fairly good agreement and the transition of the pairing symmetry in the latter material is explained as a simple doping effect. In addition, the requisite formalism for the commonly encountered nonmagnetic impurity and non-local electrodynamic effect are developed. Inspired by the success in explaining classic 115-series heavy fermion superconductors, we expect the present theory will be applied to understand other heavy fermion superconductors such as CeCu2 Si2 and more generic multi-band superconductors.
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Enhanced superconductivity in hole-doped Nb2 PdS5
Qian Chen,Xiaohui Yang,Xiaojun Yang,Jian Chen,Chenyi Shen,Pan Zhang,Yupeng Li,Qian Tao,Zhu-An Xu
Front. Phys. . 2017, 12 (5 ): 127402-.
https://doi.org/10.1007/s11467-016-0637-7
We synthesized a series of Nb2 Pd1−x Rux S5 polycrystalline samples by a solid-state reaction method and systematically investigated the Ru-doping effect on superconductivity by transport and magnetic measurements. It is found that superconductivity is enhanced with Ru doping and is quite robust upon disorder. Hall coefficient measurements indicate that the charge transport is dominated by hole-type charge carriers similar to the case of Ir doping, suggesting multi-band superconductivity. Upon Ru or Ir doping, H c 2 /T c exhibits a significant enhancement, exceeding the Pauli paramagnetic limit value by a factor of approximately 4. A comparison of T c and the upper critical field (H c 2 ) amongst the different doping elements on Pd site, reveals a significant role of spin–orbit coupling.
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Simulating heavy fermion physics in optical lattice: Periodic Anderson model with harmonic trapping potential
Yin Zhong, Yu Liu, Hong-Gang Luo
Front. Phys. . 2017, 12 (5 ): 127502-.
https://doi.org/10.1007/s11467-017-0690-x
The periodic Anderson model (PAM), where local electron orbitals interplay with itinerant electronic carriers, plays an essential role in our understanding of heavy fermion materials. Motivated by recent proposals for simulating the Kondo lattice model (KLM) in terms of alkaline-earth metal atoms, we take another step toward the simulation of PAM, which includes the crucial charge/valence fluctuation of local f-electrons beyond purely low-energy spin fluctuation in the KLM. To realize PAM, a transition induced by a suitable laser between the electronic excited and ground state of alkaline-earth metal atoms (1 S 0 ↔3 P 0 ) is introduced. This leads to effective hybridization between local electrons and conduction electrons in PAM. Generally, the SU (N ) version of PAM can be realized by our proposal, which gives a unique opportunity to detect large-N physics without complexity in realistic materials. In the present work, high-temperature physical features of standard [SU (2)] PAM with harmonic trapping potential are analyzed by quantum Monte Carlo and dynamic mean-field theory, where the Mott/orbital-selective Mott state was found to coexist with metallic states. Indications for near-future experiments are provided. We expect our theoretical proposal and (hopefully) forthcoming experiments will deepen our understanding of heavy fermion systems. At the same time, we hope these will trigger further studies on related Mott physics, quantum criticality, and non-trivial topology in both the inhomogeneous and nonequilibrium realms.
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Modification of single molecule fluorescence using external fields
Rui-Yun Chen,Guo-Feng Zhang,Cheng-Bin Qin,Yan Gao,Lian-Tuan Xiao,Suo-Tang Jia
Front. Phys. . 2017, 12 (5 ): 128101-.
https://doi.org/10.1007/s11467-016-0627-9
Controlling and manipulating the fluorescence of single fluorophores is of great interest in recent years for its potential uses in improving the performance of molecular photonics and molecular electronics, such as in organic light-emitting devices, single photon sources, organic field-effect transistors, and probes or sensors based on single molecules. This review shows how the fluorescence emission of single organic molecules can be modified using local electromagnetic fields of metallic nanostructures and electric-field-induced electron transfer. Electric-field-induced fluorescence modulation, hysteresis, and the achievement of fluorescence switch are discussed in detail.
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Minority carrier lifetime evaluation of periphery edge region in high-performance multicrystalline ingot produced by seed-assisted directional solidification
Zhong Li, Jia-Dan Li, Lin Zhuang, Rui-Jiang Hong
Front. Phys. . 2017, 12 (5 ): 128103-.
https://doi.org/10.1007/s11467-017-0708-4
A high-performance multicrystalline silicon (mc-Si) ingot was produced by seed-assisted directional solidification, and the minority carrier lifetime of the periphery edge region was evaluated. The defects and impurities in the periphery edge region of the silicon wafers were systematically studied with photoluminescence (PL) imaging, minority carrier lifetime mapping, and Fourier transform infrared (FTIR) spectroscopy. Their relationships with the minority carrier lifetime were investigated. The concentration of substitutional carbon, interstitial oxygen, and dislocation clusters is not directly correlated with the low minority carrier lifetime of the edge zone of the mc-Si ingot. Inhomogeneous grain size distribution and contamination with iron impurities were demonstrated to be the main factors affecting the low minority carrier lifetime. By controlling the impurities and improving the grain size distribution, a modified furnace was designed and a higher-quality mc-Si ingot was manufactured.
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Mesoscopic model for binary fluids
C. Echeverria, K. Tucci, O. Alvarez-Llamoza, E. E. Orozco-Guillén, M. Morales, M. G. Cosenza
Front. Phys. . 2017, 12 (5 ): 128703-.
https://doi.org/10.1007/s11467-017-0688-4
We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.
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Explosive synchronization enhances selectivity: Example of the cochlea
Chao-Qing Wang,Alain Pumir,Nicolas B. Garnier,Zong-Hua Liu
Front. Phys. . 2017, 12 (5 ): 128901-.
https://doi.org/10.1007/s11467-016-0634-x
Acoustical signal transduction in the cochlea is an active process that involves nonlinear amplification and spontaneous otoacoustic emissions. Signal transduction involves individual subunits composed of globally coupled hair cells, which can be modeled as oscillators close to a Hopf bifurcation. The coupling may induce a transition toward synchronization, which in turn leads to a strong nonlinear response. In the model studied here, the synchronization transition of the subunit is discontinuous (explosive) in the absence of an external stimulus. We show that, in the presence of an external stimulus and for a coupling strength slightly lower than the critical value leading to explosive synchronization, the response of the subunit has better frequency selectivity and a larger signal-to-noise ratio. From physiological observations that subunits are themselves coupled together, we further propose a model of the complete cochlea, accounting for the ensemble of frequencies that the organ is able to detect.
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Statistical properties of random clique networks
Yi-Min Ding, Jun Meng, Jing-Fang Fan, Fang-Fu Ye, Xiao-Song Chen
Front. Phys. . 2017, 12 (5 ): 128909-.
https://doi.org/10.1007/s11467-017-0682-x
In this paper, a random clique network model to mimic the large clustering coefficient and the modular structure that exist in many real complex networks, such as social networks, artificial networks, and protein interaction networks, is introduced by combining the random selection rule of the Erdös and Rényi (ER) model and the concept of cliques. We find that random clique networks having a small average degree differ from the ER network in that they have a large clustering coefficient and a power law clustering spectrum, while networks having a high average degree have similar properties as the ER model. In addition, we find that the relation between the clustering coefficient and the average degree shows a non-monotonic behavior and that the degree distributions can be fit by multiple Poisson curves; we explain the origin of such novel behaviors and degree distributions.
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27 articles