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Physica Scripta

Super dense coding out of thermal equilibrium

Seerat Javed, Ansha Tayyab, Muzzamal Iqbal Shaukat

Published May 28, 2024• 2 citations
Publisher

Abstract

Abstract We have examined the potentiality of superdense coding for a quantum system placed out of thermal equilibrium. To this aim, the dynamics of two two-level quantum systems are analyzed and explicit expressions for transition rates are evaluated. The dependence of superdense coding capacity on initial states is observed and examined for different ratios of anti-symmetric to symmetric transition rates. The effect of sub-radiant and super-radiant terms is interpreted. The validity of dense coding is also analyzed for different probability amplitudes and it is perceived that maximally entangled states show the highest degree of coding capacity. Moreover, the optimal time of coding capacity is greatest for initially entangled state. This strategy can be relevant to analyze further applications out of thermal equilibrium.

DOI
10.1088/1402-4896/ad5145

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Abstract We have examined the potentiality of superdense coding for a quantum system placed out of thermal equilibrium. To this aim, the dynamics of two two-level quantum systems are analyzed and explicit expressions for transition rates are evaluated. The dependence of superdense coding capacity on initial states is observed and examined for different ratios of anti-symmetric to symmetric transition rates. The effect of sub-radiant and super-radiant terms is interpreted. The validity of dense coding is also analyzed for different probability amplitudes and it is perceived that maximally entangled states show the highest degree of coding capacity. Moreover, the optimal time of coding capacity is greatest for initially entangled state. This strategy can be relevant to analyze further applications out of thermal equilibrium.
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Abstract. We investigate the creation of entanglement between two quantum emitters interacting with a realistic common stationary electromagnetic field out of thermal equilibrium. In the case of two qubits we show that the absence of equilibrium allows the generation of steady entangled states, which is inaccessible at thermal equilibrium and is realized without any further external action on the two qubits. We first give a simple physical interpretation of the phenomenon in a specific case and then we report a detailed investigation on the dependence of the entanglement dynamics on the various physical parameters involved. Sub- and super-radiant effects are discussed, and qualitative differences in the dynamics concerning both creation and protection of entanglement according to the initial two-qubit state are pointed out.
Abstract In this work, we will study thermodynamic cost of dense coding. In this regard, a scheme is proposed for quantum channel where is induced from two initially uncorrelated thermal quantum systems. At first, the quantum Fisher information and spin squeezing is used to quantify the correlation dynamics over the system. The system reveals that the dynamics of quantum correlations depends crucially on specific energy and temperature. Also, they can be utilized as control parameters for optimal dense coding. Several interesting features of the variations of the energy cost and the dense coding capacity are obtained. It can keep its own valid capacity value in a broad range of temperature by increasing in the energy value of excited states. Also, we can identify valid dense coding with the help of calculating energy cost in the system. Using this approach, identifying a critical point of this model in dense coding capacity quality can be very effective.
We investigate the creation of entanglement between two quantum emitters interacting with a realistic common stationary electromagnetic field out of thermal equilibrium. In the case of two qubits we show that the absence of equilibrium allows the generation of steady entangled states, which is inaccessible at thermal equilibrium and is realized without any further external action on the two qubits. We first give a simple physical interpretation of the phenomenon in a specific case and then we report a detailed investigation on the dependence of the entanglement dynamics on the various physical parameters involved. Sub- and super-radiant effects are discussed, and qualitative differences in the dynamics concerning both creation and protection of entanglement according to the initial two-qubit state are pointed out.