3,615 research outputs found
Deterministic versus probabilistic quantum information masking
We investigate quantum information masking for arbitrary dimensional quantum
states. We show that mutually orthogonal quantum states can always be served
for deterministic masking of quantum information. We further construct a
probabilistic masking machine for linearly independent states. It is shown that
a set of d dimensional states, , , can be probabilistically masked by a general
unitary-reduction operation if they are linearly independent. The maximal
successful probability of probabilistic masking is analyzed and derived for the
case of two initial states.Comment: 5 pages, 1 figure
Assisted state discrimination without entanglement
It is shown that the dissonance, a quantum correlation which is equal to
quantum discord for separable state, is required for assisted optimal state
discrimination. We find that only one side discord is required in the optimal
process of assisted state discrimination, while another side discord and
entanglement is not necessary. We confirm that the quantum discord, which is
asymmetric depending on local measurements, is a resource for assisted state
discrimination. With the absence of entanglement, we give the necessary and
sufficient condition for vanishing one side discord in assisted state
discrimination for a class of nonorthogonal states. As a byproduct, we find
that the positive-partial-transposition (PPT) condition is the necessary and
sufficient condition for the separability of a class of states.Comment: 6 page
Millimeter Spectral Line Mapping Observations Toward Four Massive Star Forming HII Regions
We present spectral line mapping observations toward four massive
star-forming regions (Cepheus A, DR21S, S76E and G34.26+0.15), with the IRAM 30
meter telescope at 2 mm and 3 mm bands. Totally 396 spectral lines from 51
molecules, one helium recombination line, ten hydrogen recombination lines, and
16 unidentified lines were detected in these four sources. An emission line of
nitrosyl cyanide (ONCN, 14-13) was detected in G34.26+0.15,
as first detection in massive star-forming regions. We found that the
-CH and NHD show enhancement in shocked regions as
suggested by evidences of SiO and/or SO emission. Column density and rotational
temperature of CHCN were estimated with the rotational diagram method for
all four sources. Isotope abundance ratios of C/C were derived
using HCN and its C isotopologue, which were around 40 in all four
massive star-forming regions and slightly lower than the local interstellar
value (65). N/N and O/O abundance ratios in
these sources were also derived using double isotopic method, which were
slightly lower than that in local interstellar medium. Except for Cep A,
S/S ratio in the other three targets were derived, which were
similar to that in the local interstellar medium. The column density ratios of
N(DCN)/N(HCN) and N(DCO)/N(HCO) in these sources were more than two
orders of magnitude higher than the elemental [D]/[H] ratio, which is
1.510. Our results show the later stage sources, G34.26+0.15 in
particular, present more molecular species than earlier stage ones. Evidence of
shock activity is seen in all stages studied.Comment: 32 pages, 11 figures, 8 tables, accepted for publication in MNRA
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