3,295 research outputs found
Quasi multipartite entanglement measure based on quadratic functions
We develop a new entanglement measure by extending Jaeger's Minkowskian norm
entanglement measure. This measure can be applied to a much wider class of
multipartite mixed states, although still "quasi" in the sense that it is still
incapable of dividing precisely the sets of all separable and entangled states.
As a quadratic scalar function of the system density matrix, the quasi measure
can be easily expressed in terms of the so-called coherence vector of the
system density matrix, by which we show the basic properties of the quasi
measure including (1) zero-entanglement for all separable states, (2)
invariance under local unitary operations, and (3) non-increasing under local
POVM (positive operator-valued measure) measurements. These results open up
perspectives in further studies of dynamical problems in open systems,
especially the dynamic evolution of entanglement, and the entanglement
preservation against the environment-induced decoherence effects.Comment: 10pages,1 figur
THE IMPACT OF SOCIAL PSYCHOLOGICAL FACTORS ON THE RELATIONSHIP QUALITY OF FACEBOOK USERS
Armed with the great potential for business value and social networking, social media have generated great interests in academia and practice. Rare studies investigated the impact of social psychological factors on the usage of Facebook and the formation of quality relationship. The objective of this paper is to examine the key social psychological factors to better explain the formation of quality relationship. Our proposed theoretical model combined the theories of social influence, social identity, and social presence to capture the essences of the relationship quality between users and Facebook. We conducted a survey to collect data and empirically test our proposed model. Overall, our findings provide theoretical insights to explain the influence of social psychological factors on the usage of Facebook and quality relationship. These findings also help practitioners to plan marketing strategies in better utilize social network sites
Building quantum neural networks based on swap test
Artificial neural network, consisting of many neurons in different layers, is
an important method to simulate humain brain. Usually, one neuron has two
operations: one is linear, the other is nonlinear. The linear operation is
inner product and the nonlinear operation is represented by an activation
function. In this work, we introduce a kind of quantum neuron whose inputs and
outputs are quantum states. The inner product and activation operator of the
quantum neurons can be realized by quantum circuits. Based on the quantum
neuron, we propose a model of quantum neural network in which the weights
between neurons are all quantum states. We also construct a quantum circuit to
realize this quantum neural network model. A learning algorithm is proposed
meanwhile. We show the validity of learning algorithm theoretically and
demonstrate the potential of the quantum neural network numerically.Comment: 10 pages, 13 figure
Negative entanglement measure for bipartite separable mixed states
We define a negative entanglement measure for separable states which shows
that how much entanglement one should compensate the unentangled state at least
for changing it into an entangled state. For two-qubit systems and some special
classes of states in higher-dimensional systems, the explicit formula and the
lower bounds for the negative entanglement measure have been presented, and it
always vanishes for bipartite separable pure states. The negative entanglement
measure can be used as a useful quantity to describe the entanglement dynamics
and the quantum phase transition. In the transverse Ising model, the first
derivatives of negative entanglement measure diverge on approaching the
critical value of the quantum phase transition, although these two-site reduced
density matrices have no entanglement at all. In the 1D Bose-Hubbard model, the
NEM as a function of changes from zero to negative on approaching the
critical point of quantum phase transition.Comment: 6 pages, 3 figure
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