11,327 research outputs found
Masking quantum information in multipartite scenario
Recently, Kavan Modi \emph{et al.} found that masking quantum information is
impossible in bipartite scenario in [Phys. Rev. Lett. \textbf{120}, 230501
(2018)]. This adds another item of the no-go theorems. In this paper, we
present some new schemes different from error correction codes, which show that
quantum states can be masked when more participants are allowed in the masking
process. Moreover, using a pair of mutually orthogonal Latin squares of
dimension , we show that all the level quantum states can be masked into
tripartite quantum systems whose local dimensions are or . This
highlight some difference between the no-masking theorem and the classical
no-cloning theorem or no-deleting theorem.Comment: 6 pages, 0 figur
Nodal-knot semimetals
Topological nodal-line semimetals are characterized by one-dimensional lines
of band crossing in the Brillouin zone. In contrast to nodal points, nodal
lines can be in topologically nontrivial configurations. In this paper, we
study the simplest topologically nontrivial forms of nodal line, namely, a
single nodal line taking the shape of a knot in the Brillouin zone. We
introduce a generic construction for various "nodal-knot semimetals", which
yields the simplest trefoil nodal knot and other more complicated nodal knots
in the Brillouin zone. The knotted-unknotted transitions by nodal-line
reconnections are also studied. Our work brings the knot theory to the subject
of topological semimetals.Comment: 7 pages, 5 figures. Figure quality improved
Unextendible maximally entangled bases in dxd
We investigate the unextendible maximally entangled bases in
and present a -number UMEB
construction in . For higher
dimensional case, we show that for a given -number UMEB in
, there is a -number,
, UMEB in
for any . As an
example, for systems, we show that
there are at least two sets of UMEBs which are not equivalent.Comment: Errors correcte
On small set of one-way LOCC indistinguishability of maximally entangled states
In this paper, we study the one-way local operations and classical
communication (LOCC) problem. In with
, we construct a set of one-way LOCC
indistinguishable maximally entangled states which are generalized Bell states.
Moreover, we show that there are four maximally entangled states which cannot
be perfectly distinguished by one-way LOCC measurements for any dimension
.Comment: 10 pages.Very recently, we became aware of related work \cite{Zhang2}
in which the same states in
is proved to be one-way LOCC
indistinguishable. arXiv admin note: text overlap with arXiv:1310.4220 by
other autho
Isobaric Yield Ratio Difference in Heavy-ion Collisions, and Comparison to Isoscaling
An isobaric yield ratio difference (IBD) method is proposed to study the
ratio of the difference between the chemical potential of neutron and proton to
temperature () in heavy-ion collisions. The
determined by the IBD method (IB-) is compared to the results of
the isoscaling method (IS-), which uses the isotopic or the
isotonic yield ratio. Similar distributions of the IB- and IS- are
found in the measured 140 MeV Ca + Be and the Ni +
Be reactions. The IB- and IS- both have a distribution with
a plateau in the small mass fragments plus an increasing part in the fragments
of relatively larger mass. The IB- and IS- plateaus show
dependence on the ratio of the projectile. It is suggested that the
height of the plateau is decided by the difference between the neutron density
() and the proton density () distributions of the projectiles,
and the width shows the overlapping volume of the projectiles in which
and change very little. The difference between the IB- and
IS- is explained by the isoscaling parameters being constrained by
the many isotopes and isotones, while the IBD method only uses the yields of
two isobars. It is suggested that the IB- is more reasonable than
the IS-, especially when the isotopic or isotonic ratio disobeys
the isoscaling. As to the question whether the depends on the
density or the temperature, the density dependence is preferred since the low
density can result in low temperature in the peripheral reactions.Comment: 6 pages, 6 figures, mistake of reference correcte
Chemical Property of Colliding Sources in 124,136Xe and 112,124Sn Induced Collisions in Isobaric Ratio Difference and Isoscaling Methods
The isoscaling and isobaric ratio difference (IBD) methods are used to study
the ( being the difference between the chemical
potentials of neutron and proton, and being the temperature) in the
measured 1 GeV Sn + Sn, Sn + Sn, Xe
+ Pb and Xe + Pb reactions. The isoscaling phenomena in the
Sn/Sn and the Xe/Xe reactions pairs are
investigated, and the isoscaling parameter and are obtained.
The determined by the isoscaling method (IS--) and
IBD method (IB--) in the measured Sn and Xe reactions are
compared. It is shown that in most of fragments, the IS-- and IB--
are consistent in the Xe reactions, while the IS-- and IB--
are only similar in the less neutron-rich fragments in the Sn
reactions. The shell effects in IB-- are also discussed.Comment: 5 figures, submitted to J. Phys. G: Nucl. Part. Phy
Residue Coulomb interaction among isobars and its influence in symmetry energy of neutron-rich fragment
The residue Coulomb interaction (RCI), which affects the results of symmetry
energy of neutron-rich nucleus in isobaric yield ratio (IYR) methods, is
difficult to be determined. Four RCI approximations are investigated: (1) the
M1--RCI adopting the (the ratio of Coulomb energy coefficient to
temperature) determined from the IYR of mirror-nuclei fragment; (2) the M2--RCI
by fitting the difference between IYRs; (3) the M3--RCI by adopting the
standard Coulomb energy at a temperature MeV; and (4) neglecting the RCI
among the three isobars. The M1--, M2-- and M3--RCI is found to no larger than
0.4. In particular, the M2--RCI is very close to zero. The effects of RCI in
the of fragment are also studied. The M1-- and M4-- are
found to be the lower and upper limitations of , respectively. The
M2-- overlaps the M4--, which indicates that the M2--RCI
is negligible, at the same time the RCI among the three isobars can be
neglected. A relative consistent low values of M3-- ()
are found in very neutron-rich isobars.Comment: 7pages, 7 figure
Experimental discovery of nodal chains
Three-dimensional (3D) topological nodal points, such as Weyl and Dirac nodes
have attracted wide-spread interest across multiple disciplines and diverse
material systems. Unlike nodal points that contain little structural
variations, nodal lines can have numerous topological configurations in the
momentum space, forming nodal rings, nodal chains and potentially nodal links
and nodal knots. However, nodal lines have much less development for the lack
of ideal material platforms. In condensed matter for example, nodal lines are
often fragile to spin-orbit-coupling, locating off the Fermi level, coexisting
with energy-degenerate trivial bands and dispersing strongly in energy of the
line degeneracy. Here, overcoming all above difficulties, we theoretically
predict and experimentally observe nodal chains in a metallic-mesh photonic
crystal having frequency-isolated linear bandtouching rings chained across the
entire Brillouin zone (BZ). These nodal chains are protected by mirror
symmetries and have a frequency variation less than 1%. We used angle-resolved
transmission (ART) to probe the projected bulk dispersions and performed
Fourier-transformed field scan (FTFS) to map out the surface dispersions, which
is a quadratic touching between two drumhead surface bands. Our results
established an ideal nodal-line material for further studies of topological
line-degeneracies with nontrivial connectivities, as well as the consequent
wave dynamics richer than 2D Dirac and 3D Weyl materials.Comment: 5 pages, 4 figure
Constructing unextendible product bases from the old ones
We studied the construction problem of the unextendible product basis (UPB).
We mainly give a method to construct a UPB of a quantum system through the UPBs
of its subsystem. Using this method and the UPBs which are known for us, we
construct different kinds of UPBs in general bipartite quantum system. Then we
use these UPBs to construct a family of UPBs in multipartite quantum system.
The UPBs can be used to construct the bound entangled states with different
ranks.Comment: 6 pages, 1 figure
locally indistinguishable maximally entangled states in
We give a explicit construction of locally indistinguishable orthogonal
maximally entangled states in
for any . This gives an answer to
the conjecture proposed by
S. Bandyopadhyay in 2009. Thus it reflects the nonlocality of the fundamental
feature of quantum mechanics.Comment: The paper is rewrited, especally the introduction. 5 pages, no
figure
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