Some communication protocols using entangled quantum states as channels

Daowen Qiu

Muneer Alshowkan, Khaled M. Elleithy

We propose a measurement-device-independent Quantum Key Distribution (MDI-QKD) protocol using weak coherent states and entanglement from weak coherent pulses. To overcome the side channel attacks, the sender and the receiver use decoy states to verify the security of the quantum channel. Then, they use uncorrelated entangled pairs to establish a correlated entanglement between them. The protocol establishes entangled communication channel between the sender and the receiver without performing the quantum distillation protocol. The protocol provides protection against side channel attacks such as photon-number-splitting (PNS). During the communication process, each party chooses to prepare a decoy state or a signal state. Then, they send their signals to a third party who performs Bell state measurement and then announces the measurement result. Using the information from the third party, who also could be an attacker, the sender and the receiver analyze the communication channel for any abnormalities. After verifying the security of the communication channel, the sender and the receiver establish the entanglement together for sharing secret keys.

Hung-Shen Chang, Youpeng Zhong, Audrey Bienfait +8 more

Effective quantum communication between remote quantum nodes requires high fidelity quantum state transfer and remote entanglement generation. Recent experiments have demonstrated that microwave photons, as well as phonons, can be used to couple superconducting qubits, with a fidelity limited primarily by loss in the communication channel [P. Kurpiers et al., Nature (London) 558, 264 (2018)NATUAS0028-083610.1038/s41586-018-0195-y; C. J. Axline et al., Nat. Phys. 14, 705 (2018)NPAHAX1745-247310.1038/s41567-018-0115-y; P. Campagne-Ibarcq et al., Phys. Rev. Lett. 120, 200501 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.200501; N. Leung et al., npj Quantum Inf. 5, 18 (2019)2056-638710.1038/s41534-019-0128-0; Y. P. Zhong et al., Nat. Phys. 15, 741 (2019)NPAHAX1745-247310.1038/s41567-019-0507-7; A. Bienfait et al., Science 364, 368 (2019)SCIEAS0036-807510.1126/science.aaw8415]. Adiabatic protocols can overcome channel loss by transferring quantum states without populating the lossy communication channel. Here, we present a unique superconducting quantum communication system, comprising two superconducting qubits connected by a 0.73 m-long communication channel. Significantly, we can introduce large tunable loss to the channel, allowing exploration of different entanglement protocols in the presence of dissipation. When set for minimum loss in the channel, we demonstrate an adiabatic quantum state transfer protocol that achieves 99% transfer efficiency as well as the deterministic generation of entangled Bell states with a fidelity of 96%, all without populating the intervening communication channel, and competitive with a qubit-resonant mode-qubit relay method. We also explore the performance of the adiabatic protocol in the presence of significant channel loss, and show that the adiabatic protocol protects against loss in the channel, achieving higher state transfer and entanglement fidelities than the relay method.

Simranjot Kaur, Savita Gill

Abdulbast A. Abushgra, Khaled M. Elleithy

Quantum cryptography is considered a solution for sharing secret information in a secure mode. Establishing a quantum security platform into an exciting system requires a package of stable processes. One of these processes is based on creating a Quantum Key Distribution (QKD) protocol or sharing a secret key. This paper presents a QKD protocol that utilizes two quantum channels to prepare a shared secret key. The first communication channel will be initiated by entanglement states, where the entangled photons will be emitted by a trusted third party. The second communication channel utilizes the superposition states that will be initiated by the one of the communicated parties. Moreover, the protocol produces a string of random qubits after verifying the communicated legitimate parties during entangled state channels. The produced string will reflect the shared secret key between the users.

Anders Karlsson, Mohammed Bourennane, Iulia Ghiu +2 more