We report the first experimental realization of perfect W-state in a superconducting qubit based system. In contrast to maximally entangled state, the perfect W state is different in weights and phases of the terms contained in the maximally entangled W-state. The prefect W state finds important applications in quantum information processing tasks such as perfect teleportation, superdense coding, secret sharing etc. The efficiency of generation is quantified by fidelity which is calculated by performing full quantum state tomography. To verify the presence of genuine nonlocality in the generated state, we experimentally perform Mermin's inequality tests. Further, we have also demonstrated splitting and sharing of quantum information using the experimentally generated state.
We report the first experimental realization of perfect W-state in a superconducting qubit based system. In contrast to maximally entangled state, the perfect W state is different in weights and phases of the terms contained in the maximally entangled W-state. The prefect W state finds important applications in quantum information processing tasks such as perfect teleportation, superdense coding, secret sharing etc. The efficiency of generation is quantified by fidelity which is calculated by performing full quantum state tomography. To verify the presence of genuine nonlocality in the generated state, we experimentally perform Mermin's inequality tests. Further, we have also demonstrated splitting and sharing of quantum information using the experimentally generated state.
We investigate the usefulness of a recently introduced five-qubit state by Brown et al. [I. D. K. Brown, S. Stepney, A. Sudbery, and S. L. Braunstein, J. Phys. A 38, 1119 (2005)] for quantum teleportation, quantum-state sharing, and superdense coding. It is shown that this state can be utilized for perfect teleportation of arbitrary single and two-qubit systems. We devise various schemes for quantum-state sharing of an arbitrary single- and two-particle state via cooperative teleportation. We later show that this state can be used for superdense coding as well. It is found that five classical bits can be sent by sending only three quantum bits.
Abstract We study the generation of a single photon perfect W-state. An important aspect of this perfect W-state is that it can be used for perfect teleportation and superdense coding, which are not achievable with maximally entangled W-state. Our scheme for generation involves entanglement between various path degrees of freedom of a single photon in a compact and weakly coupled integrated waveguide system, which can be fabricated precisely with a femtosecond laser direct writing technique. These platforms are interferometrically stable, scalable, less sensitive to decoherence and ensure a very low loss factor of 0.1dBcm −1 during photon propagation, and hence are ideal for generation of a perfect W-state. In addition to generation of the single photon perfect W-state, we study its non-local properties using the theory of local elements of reality.
The rapid evolution of communication networks to 5G/6G has introduced significant challenges, particularly in ensuring data security, low latency, high throughput, efficient energy consumption, dynamic access to multiple connection types, and managing the influx of connected devices. Quantum communication, leveraging entangled states like the perfect W-state, offers a promising solution with its high degree of entanglement, secure information transmission, and resilience against decoherence. However, practical applications and experimental validations remain limited, especially regarding the integration with Local Operations and Classical Communication (LOCC) protocols. Additionally, optimizing perfect W-state-based communication protocols for the splitting and sharing of quantum information has been scarcely explored. This article presents a Quantum Information Sharing and Splitting (QISS) protocol that integrates perfect W-states with LOCC to enhance 5G and 6G communication. Using the Eagle r3 processor based on superconducting qubits, our experiments demonstrated a fidelity of 0.82 ± 0.02 for the perfect W-state circuit and 0.55 ± 0.03 for the integrated W-state + LOCC in the QISS communication prototype. These findings, quantified through Quantum State Tomography, significantly improve communication security, network densification, and effectiveness. Furthermore, our research addresses existing gaps in quantum communication implementation, paving the way for scalable quantum networks and advanced encryption methods. This work marks a substantial step towards secure and efficient data transmission in next-generation communication systems.
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 they are generalized to multi-particle systems. First we describe two transformations on the shared resources for teleportation and superdense coding. With these transformations, we obtain a sufficient and necessary condition for a state of W-class being suitable for perfect teleportation and superdense coding. For the state which was thought to be not suitable for sending three classical bits by sending two qubits by Agrawal and Pati (2006 Phys. Rev. A 74 062320), we show that it may be used to fulfil that task, if entangled unitary operations on two qubits are allowed. 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 Agrawal and 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.
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.
We propose a cavity-quantum-electrodynamics scheme for one-step generation of the special configuration of W-class state [Formula: see text] which can implement deterministic teleportation, superdense coding, quantum-information splitting, and phase-covariant telecloning. We also present a method for one-step realization of a nontrivial unitary transformation [Formula: see text] which can transform a standard W state into a fully separable state. The [Formula: see text] operation plays a key role in recently proposed quantum-information processing tasks. Both the schemes are robust against decoherence. In addition, they can endure the error of controlling the interaction time between atoms and cavity. Our ideas can also be generalized to other systems.