scholarly journals Continuous-variable approach to the spectral properties and quantum states of the two-component Bose-Hubbard dimer

2017 ◽  
Vol 95 (6) ◽  
Author(s):  
F. Lingua ◽  
V. Penna
Keyword(s):  
Spectral Properties ◽  
Continuous Variable ◽  
Quantum States ◽  
Variable Approach ◽  
Two Component

Quantum dialogue protocol with four-mode continuous variable GHZ state

2019 ◽  
Vol 33 (05) ◽  
pp. 1950033 ◽  
Author(s):  
Ming-Hui Zhang ◽  
Jin-Ye Peng ◽  
Zheng-Wen Cao
Keyword(s):  
Channel Capacity ◽  
Quantum Channel ◽  
Beam Splitter ◽  
Information Leakage ◽  
Continuous Variable ◽  
Ghz State ◽  
Quantum States ◽  
Quantum Dialogue ◽  
Discrete Variable ◽  
Secret Information

Quantum dialogue can realize the mutual transmission of secret information between two legal users. In most of the existing quantum dialogue protocols, the information carriers applied in quantum dialogue are discrete variable (DV) quantum states. However, there are certain limitations on the preparation and detection of DV quantum states with current techniques. Continuous variable (CV) quantum states can overcome these problems effectively while improving the quantum channel capacity. In this paper, we propose a quantum dialogue protocol with four-mode continuous variable GHZ state. Compared with the existing CV-based quantum dialogue protocols, the protocol allows two users to transmit two groups of secret information with different lengths to each other simultaneously. The channel capacity of the protocol has been improved as each traveling mode carries two- or four-bits of information. In addition, the protocol has been proved to be secure against information leakage problem and some common attacks, such as beam splitter attack and intercept-and-resend attack.

A method for efficiently estimating non-Gaussianity of continuous-variable quantum states

2020 ◽  
Vol 74 (1) ◽  
Author(s):  
Shao-Hua Xiang ◽  
Yu-Jing Zhao ◽  
Cheng Xiang ◽  
Wei Wen ◽  
Xue-Wen Long
Keyword(s):  
Continuous Variable ◽  
Quantum States

scholarly journals Multilevel Modeling of Cognitive Diagnostic Assessment: The Multilevel DINA Example

2018 ◽  
Vol 43 (1) ◽  
pp. 34-50 ◽  
Author(s):  
Wen-Chung Wang ◽  
Xue-Lan Qiu
Keyword(s):  
Continuous Variable ◽  
Parameter Recovery ◽  
Dina Model ◽  
Variable Approach ◽  
Item Level ◽  
Multivariate Bernoulli ◽  
Level Model ◽  
Log Linear ◽  
Latent Attribute ◽  
Mathematics And Science

Many multilevel linear and item response theory models have been developed to account for multilevel data structures. However, most existing cognitive diagnostic models (CDMs) are unilevel in nature and become inapplicable when data have a multilevel structure. In this study, using the log-linear CDM as the item-level model, multilevel CDMs were developed based on the latent continuous variable approach and the multivariate Bernoulli distribution approach. In a series of simulations, the newly developed multilevel deterministic input, noisy, and gate (DINA) model was used as an example to evaluate the parameter recovery and consequences of ignoring the multilevel structures. The results indicated that all parameters in the new multilevel DINA were recovered fairly well by using the freeware Just Another Gibbs Sampler (JAGS) and that ignoring multilevel structures by fitting the standard unilevel DINA model resulted in poor estimates for the student-level covariates and underestimated standard errors, as well as led to poor recovery for the latent attribute profiles for individuals. An empirical example using the 2003 Trends in International Mathematics and Science Study eighth-grade mathematical test was provided.

TELEPORTATION OF ANY FORM OF SINGLE-MODE QUANTUM STATES

2006 ◽  
Vol 20 (02n03) ◽  
pp. 97-103
Author(s):  
TONG-QIANG SONG
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
Single Mode ◽  
Continuous Variable ◽  
Quantum States ◽  
Squeezed Vacuum ◽  
Einstein Podolsky Rosen ◽  
Epr Pair

By using the two-mode Einstein–Podolsky–Rosen (EPR) pair eigenstates or the two-mode squeezed vacuum as quantum channel we study the quantum teleportation of any form of single-mode quantum states (which include discrete and continuous variable quantum states). The elegant properties of the EPR pair eigenstates bring much convenience to our discussion.

scholarly journals About the use of fidelity in continuous variable systems

2014 ◽  
Vol 12 (02) ◽  
pp. 1461015 ◽  
Author(s):  
Antonio Mandarino ◽  
Matteo Bina ◽  
Stefano Olivares ◽  
Matteo G. A. Paris
Keyword(s):  
Physical Properties ◽  
Continuous Variable ◽  
Quantum States ◽  
High Fidelity ◽  
Non Gaussian ◽  
Additional Constraints

We present examples of continuous variable (CV) states having high fidelity to a given target, say F > 0.9 or F > 0.99, and still showing striking differences in their physical properties, including classical and quantum states within the set, separable and entangled ones, or nearly Gaussian and strongly non-Gaussian ones. We also show that the phenomenon persists also when one imposes additional constraints on the energy or the squeezing fraction of the states, thus generally questioning the use of fidelity to assess properties of CV systems without a tomographic set of additional constraints.

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