7,014 research outputs found
Order and Disorder in AKLT Antiferromagnets in Three Dimensions
The models constructed by Affleck, Kennedy, Lieb, and Tasaki describe a
family of quantum antiferromagnets on arbitrary lattices, where the local spin
S is an integer multiple M of half the lattice coordination number. The equal
time quantum correlations in their ground states may be computed as finite
temperature correlations of a classical O(3) model on the same lattice, where
the temperature is given by T=1/M. In dimensions d=1 and d=2 this mapping
implies that all AKLT states are quantum disordered. We consider AKLT states in
d=3 where the nature of the AKLT states is now a question of detail depending
upon the choice of lattice and spin; for sufficiently large S some form of Neel
order is almost inevitable. On the unfrustrated cubic lattice, we find that all
AKLT states are ordered while for the unfrustrated diamond lattice the minimal
S=2 state is disordered while all other states are ordered. On the frustrated
pyrochlore lattice, we find (conservatively) that several states starting with
the minimal S=3 state are disordered. The disordered AKLT models we report here
are a significant addition to the catalog of magnetic Hamiltonians in d=3 with
ground states known to lack order on account of strong quantum fluctuations.Comment: 7 pages, 2 figure
Optimized generation of spatial qudits by using a pure phase spatial light modulator
We present a method for preparing arbitrary pure states of spatial qudits,
namely, D-dimensional (D > 2) quantum systems carrying information in the
transverse momentum and position of single photons. For this purpose, a set of
D slits with complex transmission are displayed on a spatial light modulator
(SLM). In a recent work we have shown a method that requires a single
phase-only SLM to control independently the complex coefficients which define
the quantum state of dimension D. The amplitude information was codified by
introducing phase gratings inside each slit and the phase value of the complex
transmission was added to the phase gratings. After a spatial filtering process
we obtained in the image plane the desired qudit state. Although this method
has proven to be a good alternative to compact the previously reported
architectures, it presents some features that could be improved. In this paper
we present an alternative scheme to codify the required phase values that
minimizes the effects of temporal phase fluctuations associated to the SLM
where the codification is carried on. In this scheme the amplitudes are set by
appropriate phase gratings addressed at the SLM while the relative phases are
obtained by a lateral displacement of these phase gratings. We show that this
method improves the quality of the prepared state and provides very high
fidelities of preparation for any state. An additional advantage of this scheme
is that a complete 2\pi modulation is obtained by shifting the grating by one
period, and hence the encoding is not limited by the phase modulation range
achieved by the SLM. Numerical simulations, that take into account the phase
fluctuations, show high fidelities for thousands of qubit states covering the
whole Bloch sphere surface. Similar analysis are performed for qudits with D =
3 and D = 7.Comment: 12 pages, 7 figure
Plantio e uso da palma forrageira na alimentação de bovinos leiteiros no semiárido brasileiro.
bitstream/item/42960/1/Salete-Meta-2011.pd
Co‐existing monophasic teratoma and uterine adenocarcinoma in a female dog
Ovarian teratomas are occasionally reported in dogs; the rarest type is the monophasic teratoma,composed of tissues originating from only one germ layer. Canine endometrial adenocarcinomas are also rare in dogs and mainly affect geriatric females.
This report describes case of co-existing ovarian teratoma and uterine adenocarcinoma in a 10-year old nulliparous female Boxer presented with lethargy, anorexia and purulent vaginal discharge.
Abdominal ultrasonography evidenced pyometra and a mass in the left ovary. This was composed of
a uniform whitish tissue with multiple cystic structures. The histology revealed an atrophy of the ovarian parenchyma, compressed by a proliferation of well-differentiated nervous tissue staining positively to vimentin, S100 and neuronal specific enolase (NSE), and negatively to keratin and inhibin. The left uterine horn, whose diameter was markedly increased, showed foci of endometrial cellular atypia, evident nucleoli and mitoses, at light microscopy.
To our best knowledge, this is the first report of a coexisting ovarian monophasic teratoma and
endometrial adenocarcinoma, two rare reproductive neoplasia in dogs
Proof theory for hybrid(ised) logics
Hybridisation is a systematic process along which the characteristic features of hybrid logic, both at the syntactic and the semantic levels, are developed on top of an arbitrary logic framed as an institution. In a series of papers this process has been detailed and taken as a basis for a specification methodology for reconfigurable systems. The present paper extends this work by showing how a proof calculus (in both a Hilbert and a tableau based format) for the hybridised version of a logic can be systematically generated from a proof calculus for the latter. Such developments provide the basis for a complete proof theory for hybrid(ised) logics, and thus pave the way to the development of (dedicated) proof support.The authors are grateful to Torben Bräuner for helpful, inspiring discussions, and to the anonymous referees for their detailed comments.
This work is funded by ERDF—European Regional Development Fund, through the COMPETE Programme, and by National Funds through Fundação para a Ciência e a Tecnologia(FCT) within project PTDC/EEI-CTP/4836/2014. Moreover, the first and the second authors are sponsored by FCT grants SFRH/BD/52234/2013 and SFRH/BPD/103004/2014, respectively. M. Mar-tins is also supported by the EU FP7 Marie Curie PIRSES-GA-2012-318986 project GeTFun: Generalizing Truth-Functionality and FCT project UID/MAT/04106/2013 through CIDMA. L.Barbosa is further supported by FCT in the context of SFRH/B-SAB/113890/2015
Noncommutative Metafluid Dynamics
In this paper we define a noncommutative (NC) Metafluid Dynamics
\cite{Marmanis}. We applied the Dirac's quantization to the Metafluid Dynamics
on NC spaces. First class constraints were found which are the same obtained in
\cite{BJP}. The gauge covariant quantization of the non-linear equations of
fields on noncommutative spaces were studied. We have found the extended
Hamiltonian which leads to equations of motion in the gauge covariant form. In
addition, we show that a particular transformation \cite{Djemai} on the usual
classical phase space (CPS) leads to the same results as of the
-deformation with . Besides, we will shown that an additional
term is introduced into the dissipative force due the NC geometry. This is an
interesting feature due to the NC nature induced into model.Comment: 11 page
Interference and complementarity for two-photon hybrid entangled states
In this work we generate two-photon hybrid entangled states (HES), where the
polarization of one photon is entangled with the transverse spatial degree of
freedom of the second photon. The photon pair is created by parametric
down-conversion in a polarization-entangled state. A birefringent double-slit
couples the polarization and spatial degrees of freedom of these photons and
finally, suitable spatial and polarization projections generate the HES. We
investigate some interesting aspects of the two-photon hybrid interference, and
present this study in the context of the complementarity relation that exists
between the visibilities of the one- and two-photon interference patterns.Comment: 10 pages, 4 figures. Accepted in Physical Review
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