2,177 research outputs found
X(1835): A Possible Baryonium?
We point out that (1) the large coupling and suppressed mesonic
coupling of X(1835) and (2) the suppression of the three-body strange final
states strongly indicate that X(1835) may be a baryonium. We also
point out that the branching ratio of should be bigger
than that of . If BES further confirms the
non-observation of X(1835) in the channel, that will be very
puzzling. Finally, X(1835) may be used a tetraquark generator if X(1835) is
really established as a baryonium state.Comment: Comments and suggestions welcom
Anomalous Electron Trajectory in Topological Insulators
We present a general theory about electron orbital motions in topological
insulators. An in-plane electric field drives spin-up and spin-down electrons
bending to opposite directions, and skipping orbital motions, a counterpart of
the integer quantum Hall effect, are formed near the boundary of the sample.
The accompanying Zitterbewegung can be found and controlled by tuning external
electric fields. Ultrafast flipping electron spin leads to a quantum side jump
in the topological insulator, and a snake-orbit motion in two-dimensional
electron gas with spin-orbit interactions. This feature provides a way to
control electron orbital motion by manipulating electron spin.Comment: 5 pages and 4 figures for the letter, 6 pagers for the online
supplemental materia
Phase transitions and thermodynamics of the two-dimensional Ising model on a distorted Kagom\'{e} lattice
The two-dimensional Ising model on a distorted Kagom\'{e} lattice is studied
by means of exact solutions and the tensor renormalisation group (TRG) method.
The zero-field phase diagrams are obtained, where three phases such as
ferromagnetic, ferrimagnetic and paramagnetic phases, along with the
second-order phase transitions, have been identified. The TRG results are quite
accurate and reliable in comparison to the exact solutions. In a magnetic
field, the magnetization (), susceptibility and specific heat are studied by
the TRG algorithm, where the plateaux are observed in the magnetization
curves for some couplings. The experimental data of susceptibility for the
complex Co(N)(bpg) DMF are fitted with the TRG results,
giving the couplings of the complex and
Improving the security of quantum direct communication with authentication
Two protocols of quantum direct communication with authentication [Phys. Rev.
A {\bf 73}, 042305 (2006)] are recently proposed by Lee, Lim and Yang. In this
paper we will show that in the two protocols the authenticator Trent should be
prevented from knowing the secret message of communication. The first protocol
can be eavesdropped by Trent using the the intercept-measure-resend attack,
while the second protocol can be eavesdropped by Trent using single-qubit
measurement. To fix these leaks, I revise the original versions of the
protocols by using the Pauli-Z operation instead of the original
bit-flip operation . As a consequence, the protocol securities are improved.Comment: Any suggestion,comment or help is welcome
Emergent spin-1 trimerized valence bond crystal in the spin-1/2 Heisenberg model on the star lattice
We explore the frustrated spin- Heisenberg model on the star lattice
with antiferromagnetic (AF) couplings inside each triangle and ferromagnetic
(FM) inter-triangle couplings (), and calculate its magnetic and
thermodynamic properties. We show that the FM couplings do not sabotage the
magnetic disordering of the ground state due to the frustration from the AF
interactions inside each triangle, but trigger a fully gapped
inversion-symmetry-breaking trimerized valence bond crystal (TVBC) with
emergent spin-1 degrees of freedom. We discover that with strengthening ,
the system scales exponentially, either with or without a magnetic field :
the order parameter, the five critical fields that separate the -
ground-state phase diagram into six phases, and the excitation gap obtained by
low-temperature specific heat, all depend exponentially on . We calculate
the temperature dependence of the specific heat, which can be directly compared
with future experiments.Comment: 7 pages, 6 figure
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