Fiktív vallomás és szövegműködés. Dosztojevszkij: ,Ördögök’

A vallomásos elbeszélés különös világossággal mutat rá a nyelvi működés ama sajátosságára, hogy nem vonható éles határ a reprezentációs (leíró, megjelenítő) nyelvi funkció és a fikcióteremtő potencialitás között

Entanglement Detection in the Stabilizer Formalism

We investigate how stabilizer theory can be used for constructing sufficient conditions for entanglement. First, we show how entanglement witnesses can be derived for a given state, provided some stabilizing operators of the state are known. These witnesses require only a small effort for an experimental implementation and are robust against noise. Second, we demonstrate that also nonlinear criteria based on uncertainty relations can be derived from stabilizing operators. These criteria can sometimes improve the witnesses by adding nonlinear correction terms. All our criteria detect states close to Greenberger-Horne-Zeilinger states, cluster and graph states. We show that similar ideas can be used to derive entanglement conditions for states which do not fit the stabilizer formalism, such as the three-qubit W state. We also discuss connections between the witnesses and some Bell inequalities.Comment: 15 pages including 2 figures, revtex4; typos corrected, presentation improved; to appear in PR

Cluster mean-field study of the parity conserving phase transition

The phase transition of the even offspringed branching and annihilating random walk is studied by N-cluster mean-field approximations on one-dimensional lattices. By allowing to reach zero branching rate a phase transition can be seen for any N <= 12.The coherent anomaly extrapolations applied for the series of approximations results in $\nu_{\perp}=1.85(3)$ and $\beta=0.96(2)$.Comment: 6 pages, 5 figures, 1 table included, Minor changes, scheduled for pubication in PR

Number operator-annihilation operator uncertainty as an alternative of the number-phase uncertainty relation

We consider a number operator-annihilation operator uncertainty as a well behaved alternative to the number-phase uncertainty relation, and examine its properties. We find a formulation in which the bound on the product of uncertainties depends on the expectation value of the particle number. Thus, while the bound is not a constant, it is a quantity that can easily be controlled in many systems. The uncertainty relation is approximately saturated by number-phase intelligent states. This allows us to define amplitude squeezing, connecting coherent states to Fock states, without a reference to a phase operator. We propose several setups for an experimental verification.Comment: 8 pages including 3 figures, revtex4; v2: typos corrected, presentation improved; v3: presentation considerably extended; v4: published versio

The Place of Čechov’s Dramas in Peter Szondi’s Theory of Drama

The paper examines Peter Szondi’s theory of drama from two perspectives: 1. what traces of his new approach – i.e. textual interpretation – can be found in his early works; 2. to what extent are Szondi’s conclusions valid and original with respect to Čechov’s dramatic works? I identify common characteristics of Szondi’s conception of literature, formalist poetics, and phenomenological approaches. I also analyse two features of modern drama, epicization and the role of the intimate Self, through interpretations of Čechov’s dramas. I come to the conclusion that monologues acquire a narrative function in Čechov’s works, while through inner speech they also preserve the linguistic compactness characteristic of lyric poetry, i.e. the sound effects (alliteration, assonance and richly metaphorical language), which generates meaning-producing processes in the dramatic text

Two-setting Bell Inequalities for Graph States

We present Bell inequalities for graph states with high violation of local realism. In particular, we show that there is a two-setting Bell inequality for every nontrivial graph state which is violated by the state at least by a factor of two. These inequalities are facets of the convex polytope containing the many-body correlations consistent with local hidden variable models. We first present a method which assigns a Bell inequality for each graph vertex. Then for some families of graph states composite Bell inequalities can be constructed with a violation of local realism increasing exponentially with the number of qubits. We also suggest a systematic way for obtaining Bell inequalities with a high violation of local realism for arbitrary graphs.Comment: 8 pages including 2 figures, revtex4; minor change

Pairing in fermionic systems: A quantum information perspective

The notion of "paired" fermions is central to important condensed matter phenomena such as superconductivity and superfluidity. While the concept is widely used and its physical meaning is clear there exists no systematic and mathematical theory of pairing which would allow to unambiguously characterize and systematically detect paired states. We propose a definition of pairing and develop methods for its detection and quantification applicable to current experimental setups. Pairing is shown to be a quantum correlation different from entanglement, giving further understanding in the structure of highly correlated quantum systems. In addition, we will show the resource character of paired states for precision metrology, proving that the BCS states allow phase measurements at the Heisenberg limit.Comment: 23 pages, 4 figure