The one-way information deficit for a class of two-qubit states

2015 ◽  
Vol 13 (02) ◽  
pp. 1550012
Author(s):  
H. Eftekhari ◽  
E. Faizi

So far, one-way information deficit (OWID) has been calculated explicitly only for Bell-diagonal states and the four-parameter family of X-states with additional assumptions and expressions for more general quantum states are not known. In this paper, we derive explicit expressions for OWID for a larger class of two-qubit states, namely, a five-parameter family of two-qubit states. The dynamic behavior of the OWID under decoherence channel is investigated and it is shown that the OWID is more robust against the decoherence than the entanglement.

2013 ◽  
Vol 13 (3&4) ◽  
pp. 210-220
Author(s):  
Christopher Eltschka ◽  
Jens Siewert

Recently, a new type of symmetry for three-qubit quantum states was introduced, the so-called Greenberger-Horne-Zeilinger (GHZ) symmetry. It includes the operations which leave the three-qubit standard GHZ state unchanged. This symmetry is powerful as it yields families of mixed states that are, on the one hand, complex enough from the physics point of view and, on the other hand, simple enough mathematically so that their properties can be characterized analytically. We show that by using the properties of GHZ-symmetric states it is straightforward to derive optimal witnesses for detecting class-specific entanglement in arbitrary three-qubit states.


2021 ◽  
pp. 2150249
Author(s):  
Vikram Verma

In this paper, by utilizing a nine-qubit entangled state as a quantum channel, we propose new schemes for symmetric and asymmetric cyclic controlled quantum teleportation (CYCQT). In our proposed schemes, four participants Alice, Bob, Charlie and David teleport their unknown quantum states cyclically among themselves with the help of a controller Eve. No participants can reconstruct the original states sent from the respective senders without the permission of the controller. Also, by considering same nine-qubit entangled state as a quantum channel, we propose a generalized scheme for CYCQT of multi-qubit states. In contrast to the previous CYCQT schemes involving three communicators and a controller, there are four communicators and a controller in the proposed schemes. Also, compared with previous CYCQT schemes, our proposed CYCQT schemes require less consumption of quantum resource and the intrinsic efficiency of the generalized scheme increases with the increase of number of qubits in the information states.


2020 ◽  
pp. 145-161

Resumen Las organizaciones en general, y las cooperativas en particular, han sido objeto de cambios progresivos producto del sistema globalizado y de mercados diferenciados, que las han obligado a adoptar nuevos modelos organizacionales fundamentados en las premisas de añadir flexibilidad y valor para ser más competitivas, productivas e innovadoras. En ese contexto, el objetivo del artículo es determinar las formas organizativas modernas que presentan empresas grandes del sector cooperativo multiactivo colombiano, considerando sus estructuras, conductas y procedimientos. El enfoque fue cuantitativo, con un alcance descriptivo, transversal. Se utilizó la técnica de encuesta aplicada a 126 empleados en una población de 28 cooperativas seleccionadas intencionalmente. Los resultados muestran que la mayoría de los encuestados considera que las cooperativas multiactivas analizadas presentan formas estructurales, comportamentales y procedimentales modernas, basadas en la existencia de estructuras flexibles y el comportamiento dinámico de su personal. Se concluye que las empresas grandes del sector cooperativo estudiadas no aplican un solo tipo de formas organizativas, sino que toman la que mejor se adapten a las necesidades propias del sector, para convertirse en referentes de organizaciones que hacen posible la aplicación del nuevo paradigma imperante en la sociedad. Abstract Organizations in general, and particularly cooperatives, have been subject to progressive changes as a result of the globalized system and different markets, which have forced them to adopt new organizational models based on the premises of adding flexibility and value to be more competitive, productive, and innovative. In this context, the objective of the article is to determine the modern organizational forms that large companies of the Colombian multi-asset cooperative sector have, considering their structures, behaviors and procedures. The approach was quantitative, with a descriptive, transversal scope. The technique used in this article is a survey applied to 126 employees in a population of 28 intentionally selected cooperatives. The results show that the majority of respondents consider that the multi-asset cooperatives analyzed show modern structural, behavioral and procedural forms, based on the existence of flexible structures and the dynamic behavior of their staff. It is concluded that the large companies in the cooperative sector studied do not apply a single type of organizational form, but take the one that best suits the sector's own needs, to become benchmarks for organizations that make possible the application of the new prevailing paradigm in the society.


2004 ◽  
Vol 36 (11) ◽  
pp. 724-728 ◽  
Author(s):  
Jun-Jun Lu ◽  
Ming Ming ◽  
Yi Yang ◽  
Jia Wu ◽  
Bo Li ◽  
...  

Abstract Transient dynamic behavior of the excited bacteriorhodopsin (BR), which was isolated from the strain H. salinarum, was studied at excitation wavelength from 585 to 639 nm. With the one-color femtosecond (fs) pump-probe technique, we revealed the primary events in BR's photocycle that took place in an ultrafast time scale. From the analysis of the decay components of the dynamical traces, it was evident that the isomerization of the retinal chromophore in BR and the intermediate J's formation occurred within 500 fs. BR exhibited pH-dependent dynamical behaviors. When the medium pH was between 5 and 9, the BR ultrafast dynamics has no obvious change. In contrast, the dynamical curves were obviously affected when the pH was out of that region.


Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 19
Author(s):  
Li-Yi Hsu ◽  
Shoichi Kawamoto

While Bell operators are exploited in detecting Bell nonlocality and entanglement classification, we demonstrate their usefulness in exploring Einstein–Podolsky–Rosen (EPR) steering, which represents the quantum correlation intermediate between entanglement and Bell nonlocality. We propose a task function that detects steerability of multi-qubit states in bipartite scenarios. A novel necessary and sufficient steering criterion is based on the superposition of the recursive Bell operators which are often employed for detecting Bell nonlocality. Utilizing the task function we can (i) reveal the one-to-one mapping relation between joint measurability and unsteerability, (ii) geometrically depict and compare the entanglement classification and the steering criteria and propose a geometrical measure, and (iii) compare the EPR steering with Bell nonlocality using an alternative task function. We extend the result to detect EPR steering for multi-qutrit cases and some numerical results are illustrated as examples. Finally, the steering criteria in a star-shaped quantum network is studied to see how the result is applied to a genuine multipartite steering case.


Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 684
Author(s):  
Yoshifumi Nakata ◽  
Mio Murao

When a quantum pure state is drawn uniformly at random from a Hilbert space, the state is typically highly entangled. This property of a random state is known as generic entanglement of quantum states and has been long investigated from many perspectives, ranging from the black hole science to quantum information science. In this paper, we address the question of how symmetry of quantum states changes the properties of generic entanglement. More specifically, we study bipartite entanglement entropy of a quantum state that is drawn uniformly at random from an invariant subspace of a given symmetry. We first extend the well-known concentration formula to the one applicable to any subspace and then show that 1. quantum states in the subspaces associated with an axial symmetry are still highly entangled, though it is less than that of the quantum states without symmetry, 2. quantum states associated with the permutation symmetry are significantly less entangled, and 3. quantum states with translation symmetry are as entangled as the generic one. We also numerically investigate the phase-transition behavior of the distribution of generic entanglement, which indicates that the phase transition seems to still exist even when random states have symmetry.


2012 ◽  
Vol 12 (1) ◽  
pp. 279-294 ◽  
Author(s):  
Ming-Xing Luo ◽  
Yun Deng ◽  
Xiu-Bo Chen ◽  
Yi-Xian Yang

2003 ◽  
Vol 2003 (34) ◽  
pp. 2139-2146 ◽  
Author(s):  
Nuno Martins ◽  
Ricardo Severino ◽  
J. Sousa Ramos

We compute theK-groups for the Cuntz-Krieger algebras𝒪A𝒦(fμ), whereA𝒦(fμ)is the Markov transition matrix arising from the kneading sequence𝒦(fμ)of the one-parameter family of real quadratic mapsfμ.


2007 ◽  
Vol 22 (23) ◽  
pp. 1717-1726 ◽  
Author(s):  
S. M. ROY ◽  
D. ATKINSON ◽  
G. AUBERSON ◽  
G. MAHOUX ◽  
V. SINGH

An eight-parameter family of the most general non-negative quadruple probabilities is constructed for EPR–Bohm–Aharonov experiments when only three pairs of analyser settings are used. It is a simultaneous representation of three different Bohr-incompatible experimental configurations involving mutually noncommuting observables valid for arbitrary quantum states.


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