19,119 research outputs found
An exercise on developing an ontology-epistemology about schizophrenia and neuroanatomy
This paper describes preliminary ideas on formalizing some concepts of neuroanatomy into ontological and epistemological terms. We envisage the application of this ontology on the assimilation of facts about medical knowledge about neuroimages from schizophrenic patients
Pair-Density-Wave Order and Paired Fractional Quantum Hall Fluids
The properties of the isotropic incompressible fractional quantum
Hall (FQH) state are described by a paired state of composite fermions in zero
(effective) magnetic field, with a uniform pairing order parameter,
which is a non-Abelian topological phase with chiral Majorana and charge modes
at the boundary. Recent experiments suggest the existence of a proximate
nematic phase at . This finding motivates us to consider an
inhomogeneous paired state - a pair-density-wave (PDW) - whose
melting could be the origin of the observed liquid-crystalline phases. This
state can viewed as an array of domain and anti-domain walls of the
order parameter. We show that the nodes of the PDW order parameter, the
location of the domain walls (and anti-domain walls) where the order parameter
changes sign, support a pair of symmetry-protected counter-propagating Majorana
modes. The coupling behavior of the domain wall Majorana modes crucially
depends on the interplay of the Fermi energy and the PDW pairing energy
. The analysis of this interplay yields a rich set of
topological states. The pair-density-wave order state in paired FQH system
provides a fertile setting to study Abelian and non-Abelian FQH phases - as
well as transitions thereof - tuned by the strength of the paired liquid
crystalline order.Comment: 27 pages, 11 figures; Published versio
Physically Realizable Entanglement by Local Continuous Measurements
Quantum systems prepared in pure states evolve into mixtures under
environmental action. Physically realizable ensembles are the pure state
decompositions of those mixtures that can be generated in time through
continuous measurements of the environment. Here, we define physically
realizable entanglement as the average entanglement over realizable ensembles.
We optimize the measurement strategy to maximize and minimize this quantity
through local observations on the independent environments that cause two
qubits to disentangle in time. We then compare it with the entanglement bounds
for the unmonitored system. For some relevant noise sources the maximum
realizable entanglement coincides with the upper bound, establishing the scheme
as an alternative to locally protect entanglement. However, for local
strategies, the lower bound of the unmonitored system is not reached.Comment: version 2; 5 pages, 1 figure; added references
- …