In this article we will consider the entanglement states and we will formulate the density matrix and the expectation value of entanglement state to mathematics and also we will explain the applications of entanglement states in superdense coding and sending information ( qubits transfer).
Quantum teleportation is a technique of sending information from one place to another place. Distance between two points can be hundreds of thousands of lightyears. For quantum teleportation, there is no need for a channel between two points when sending a state vector from one place to another. Since classical information sharing is possible, it is also possible to send a state vector from one place to another place. Teleportation is the transfer of a quantum state from one place to another through classical channels. Superdense coding, a dual to teleportation, uses a single quantum bit to transmit two bits classical information. Superdense coding uses a qubit to transfer two classical bits, while teleportation performs one qubit transfer using two classical bits. In this article, teleportation, superdense coding algorithms, and the Bell’s inequality test in which Bell’s inequality is violated with quantum mechanics are performed on both Qiskit and International Business Machines circuit composer, and results are compared and presented in detail. The results revealed that whether a faster-than-light signal transfer is possible using quantum mechanics depends on whether a copy of the quantum state is created or not. Finally, Bell’s inequality created by classical logic violated by quantum mechanics is shown by experimental results. Cite this article as: Y. Poyraz Koçak and S. Sevgen, "Superdense coding, teleportation algorithms, and bell’s inequality test in qiskit and IBM circuit composer," Electrica., 22(2), 120-131, 2022.
Quantum entanglement stands as one of the most intriguing phenomena in quantum mechanics, defying classical intuition and paving the way for revolutionary advancements in information processing. the fundamentals of quantum entanglement and explores its applications in quantum information processing. Beginning with a concise overview of entanglement theory, we delve into various protocols and techniques that leverage entangled states to perform tasks such as quantum teleportation, superdense coding, and quantum cryptography. Furthermore, we discuss recent developments in the field, including entanglement-based quantum key distribution schemes and entanglement swapping protocols. Through a comprehensive examination of both theoretical principles and experimental implementations, this paper elucidates the pivotal role of quantum entanglement in shaping the landscape of quantum information processing, with implications for secure communication, computational speedup, and future quantum technologies.
As we know, the states of triqubit systems have two important classes: GHZ-class and W-class. In this paper, the states of W-class are considered for teleportation and superdense coding, and are generalized to multi-particle systems. First we describe two transformations of the shared resources for teleportation and superdense coding, which allow many new protocols from some known ones for that. As an application of these transformations, we obtain a sufficient and necessary condition for a state of W-class being suitable for perfect teleportation and superdense coding. As another application, we find that state ∣W>123=1/2(∣100>123+∣010>123+sqrt2∣001>123) can be used to transmit three classical bits by sending two qubits, which was considered to be impossible by P. Agrawal and A. Pati [Phys. Rev. A to be published]. We generalize the states of W-class to multi-qubit systems and multi-particle systems with higher dimension. We propose two protocols for teleportation and superdense coding by using W-states of multi-qubit systems that generalize the protocols by using ∣W>123 proposed by P. Agrawal and A. Pati. We obtain an optimal way to partition some W-states of multi-qubit systems into two subsystems, such that the entanglement between them achieves maximum value.
Superdense coding is a paradigmatic protocol in quantum information science, employing a quantum communication channel to send classical information more efficiently. As we show here, it can be understood as a particular case of a prepare and measure experiment, a scenario that has attracted growing attention for its fundamental and practical applications. Formulating superdense coding as a prepare and measure scenario allows us to provide a semi-device-independent witness of entanglement that significantly improves over previous tests. Furthermore, we also show how to adapt our results into self-testing of maximally entangled states and also provide a semidefinite program formulation allowing one to efficiently optimize, for any shared quantum state, the probability of success in the superdense coding protocol.
Quantum entangled states play very important roles in quantum information processing,such as quantum teleportation,dense coding,error correction,cryptography,and computation.The theory of entanglement mainly concerns the characterization of quantum entanglement and the classification of quantum states,as well as its applications in quantum information processing.We present some basic concepts and results,including:the relationship between locality and reality in quantum mechanics and Bell inequalities,and that between Bell inequalities and the separability of quantum states;the definition of separability for pure and mixed quantum states,and some separability criteria such as the positive map approach,positive partial transpose,reduction criterion,realignment,entanglement witnesses,and the covariance matrix approach and local uncertainty relations;some entanglement measures such as the entanglement of formation,concurrence,relative entropy,negativity,tangle,entanglement of assistance,and their estimation;the change in entanglement when the physical system evolves or undergoes interaction with the environment.