Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Sensors

Investigating Imperfect Cloning for Extending Quantum Communication Capabilities

Masab Iqbal, Luis Velasco, Nelson M. S. Costa, Antonio Napoli, João Pedro, Marc Ruiz

Published Sep 14, 2023• 6 citations
Publisher

Abstract

Quantum computing allows the implementation of powerful algorithms with enormous computing capabilities and promises a secure quantum Internet. Despite the advantages brought by quantum communication, certain communication paradigms are impossible or cannot be completely implemented due to the no-cloning theorem. Qubit retransmission for reliable communications and point-to-multipoint quantum communication (QP2MP) are among them. In this paper, we investigate whether a Universal Quantum Copying Machine (UQCM) generating imperfect copies of qubits can help. Specifically, we propose the Quantum Automatic Repeat Request (QARQ) protocol, which is based on its classical variant, as well as to perform QP2MP communication using imperfect clones. Note that the availability of these protocols might foster the development of new distributed quantum computing applications. As current quantum devices are noisy and they decohere qubits, we analyze these two protocols under the presence of various sources of noise. Three major quantum technologies are studied for these protocols: direct transmission (DT), teleportation (TP), and telecloning (TC). The Nitrogen-Vacancy (NV) center platform is used to create simulation models. Results show that TC outperforms TP and DT in terms of fidelity in both QARQ and QP2MP, although it is the most complex one in terms of quantum cost. A numerical study shows that the QARQ protocol significantly improves qubit recovery and that creating more clones does not always improve qubit recovery.

DOI
10.3390/s23187891

Related papers

Reliable Quantum Communication

Masab Iqbal, Morteza Ahmadian, Luis Velasco +1 more

The quantum internet, which will be a hybrid of quantum and classical networks, is expected to provide information-theoretic security for data transmission. Classical networks have well-established protocols for reliable end-to-end transmission that use duplicating the classical bits implicitly. However, due to the no-cloning theorem, quantum bits (qubits) cannot be copied. In this paper, we propose to use a Universal Quantum Copying Machine (UQCM) to create imperfect clones and summarizes the Quantum Automatic Repeat Request (QARQ) protocol, which is inspired by its classical counterpart. To investigate the viability of QARQ, a simulation platform is created considering Nitrogen-vacancy (NV) center qubit platform that implements QARQ for quantum communication. The results explore the applications it is suitable for while maintaining enough quality of the qubit state. Two major quantum technologies are studied for these protocols: Direct Transmission (DT), and Teleportation (TP). It has been shown that for short distance communication DT provides better fidelity than TP while for long-distance communication TP outperforms DT and hence improves the QARQ performance as well.

International Conference on Transparent Optical Networks•Jul 2, 2023•0 citations

Quantum Bit Retransmission Using Universal Quantum Copying Machine

Masab Iqbal, Luis Velasco, Marc Ruiz +3 more

Quantum internet, which is expected to be a combination of quantum and classical networks, promises to provide information-theoretic security for data exchange. Classical networks have well-established protocols for reliable end-to-end transmission that implicitly make use of duplicating classical bits. However, quantum bits (qubits) cannot be copied due to the no-cloning theorem. In this paper, we take advantage of the principle of creating imperfect clones using a Universal Quantum Copying Machine (UQCM) and propose the Quantum Automatic Repeat Request (QARQ) protocol, inspired by its classical equivalent. A simulation platform has been developed to study the feasibility of QARQ. Results show that our proposal is well suited for applications that are compatible with low fidelity requirements.

International Conference on Optical Network Design and Modeling (ONDM)•May 16, 2022•5 citations

Optimized Telecloning Circuits: Theory and Practice of Nine NISQ Clones

Elijah Pelofske, Andreas Bärtschi, Stephan Eidenbenz

Although perfect copying of an unknown quantum state is not possible, approximate cloning is possible in quantum mechanics. Quantum telecloning is a variant of approximate quantum cloning which uses quantum teleportation to allow for the use of classical communication to create physically separate clones of a quantum state. We present results of a of 1 →9 universal, symmetric, optimal quantum telecloning implementation on a cloud accessible quantum computer - the Quantinuum H1-1 device. The H1-1 device allows direct creation of the telecloning protocol due to real time classical if-statements that are conditional on the mid-circuit measurement outcome of a Bell measurement. In this implementation, we also provide an improvement over previous work for the circuit model description of quantum telecloning, which reduces the required gate depth and gate count for an all-to-all connectivity. The demonstration of creating 9 approximate clones on a quantum processor is the largest number of clones that has been generated, telecloning or otherwise.

arXiv:2210.10164•IEEE International Conference on Rebooting Computing (ICRC)•Dec 1, 2022•2 citations

Quantum Telecloning on NISQ Computers

Elijah Pelofske, Andreas Bärtschi, Bryan Garcia +2 more

Due to the no-cloning theorem, generating perfect quantum clones of an arbitrary unknown quantum state is not possible, however approximate quantum clones can be constructed. Quantum telecloning is a protocol that originates from a combination of quantum teleportation and quantum cloning. Here we present 1 → 2 and 1 → 3 quantum telecloning circuits, with and without ancilla, that are theoretically optimal (meaning the clones have the highest fidelity allowed by quantum mechanics), universal (meaning the clone fidelity is independent of the state being cloned), and symmetric (meaning the clones all have the same fidelity). We implement these circuits on gate model IBMQ and Quantinuum NISQ hardware and quantify the clone fidelities using parallel single qubit state tomography. Quantum telecloning using mid-circuit measurement with classical feed-forward control (i.e. real time if statements) is demonstrated on the Quantinuum H1-2 device. Two alternative implementations of quantum telecloning, deferred measurement and post selection, are demonstrated on ibmq_montreal, where mid-circuit measurements with real time if statements are not available. Our results show that NISQ devices can achieve near-optimal quantum telecloning fidelity; for example the Quantinuum H1-2 device running the telecloning circuits without ancilla achieved a mean clone fidelity of 0.824 with standard deviation of 0.024 for two clone circuits and 0.765 with standard deviation of 0.022 for three clone circuits. The theoretical fidelity limits are $0.8\bar 3$ for two clones and $0.\bar 7$ for three clones. This demonstrates the viability of performing experimental analysis of quantum information networks and quantum cryptography protocols on NISQ computers.

arXiv:2205.00125•IEEE International Conference on Quantum Computing and Engineering (QCE)•Sep 1, 2022•7 citations

Optimizing Intruder Evasion and Key Recovery on BB84 Quantum Protocol via Varying Rotational Angles with a Universal Quantum Copying Machine

Yousef Ahmed Y. Altaher

The no-cloning theorem provided a security feature that enabled the BB84 protocol to be a possible quantum protocol for secure key exchange. A possible method to undermine the security of the BB84 exists by utilizing a UQCM to imperfectly copy the qubits. However, due to the introduced errors, detections of an intruder using a UQCM is possible, in addition to the imperfect recovered key by the intruder. In this paper, a simulation of an intruder intercepting a 5 -qubit BB84 protocol execution with 1000 randomly generated sets of angles, 100 -time of BB84 simulation, for each set, is used to estimate the probability of detection and key recovery with a UQCM. Despite that a UQCM is universally optimized with the values on the 1998 paper of Vladimr R. Buzek and Mark Hillery, the simulations provided different values that can reduce the detection rate while increasing the probability of a successful key recovery. Moreover, there are multiple rotational angles that provides similar key recovery probability with varying degrees of discoverability.

Photonics & Electromagnetics Research Symposium - Spring (PIERS-Spring)•May 4, 2025•0 citations

Experimental demonstration of entanglement-enabled universal quantum cloning in a circuit

Zhen‐Biao Yang, Pei-Rong Han, Xin-Jie Huang +6 more

Abstract No-cloning theorem forbids perfect cloning of an unknown quantum state. A universal quantum cloning machine (UQCM), capable of producing two copies of any input qubit with the optimal fidelity, is of fundamental interest and has applications in quantum information processing. This is enabled by delicately tailored nonclassical correlations between the input qubit and the copying qubits, which distinguish the UQCM from a classical counterpart, but whose experimental demonstrations are still lacking. We here implement the UQCM in a superconducting circuit and investigate these correlations. The measured entanglements well agree with our theoretical prediction that they are independent of the input state and thus constitute a universal quantum behavior of the UQCM that was not previously revealed. Another feature of our experiment is the realization of deterministic and individual cloning, in contrast to previously demonstrated UQCMs, which either were probabilistic or did not constitute true cloning of individual qubits.

arXiv:1909.03170•npj Quantum Information•Feb 26, 2021•19 citations
Quantum computing allows the implementation of powerful algorithms with enormous computing capabilities and promises a secure quantum Internet. Despite the advantages brought by quantum communication, certain communication paradigms are impossible or cannot be completely implemented due to the no-cloning theorem. Qubit retransmission for reliable communications and point-to-multipoint quantum communication (QP2MP) are among them. In this paper, we investigate whether a Universal Quantum Copying Machine (UQCM) generating imperfect copies of qubits can help. Specifically, we propose the Quantum Automatic Repeat Request (QARQ) protocol, which is based on its classical variant, as well as to perform QP2MP communication using imperfect clones. Note that the availability of these protocols might foster the development of new distributed quantum computing applications. As current quantum devices are noisy and they decohere qubits, we analyze these two protocols under the presence of various sources of noise. Three major quantum technologies are studied for these protocols: direct transmission (DT), teleportation (TP), and telecloning (TC). The Nitrogen-Vacancy (NV) center platform is used to create simulation models. Results show that TC outperforms TP and DT in terms of fidelity in both QARQ and QP2MP, although it is the most complex one in terms of quantum cost. A numerical study shows that the QARQ protocol significantly improves qubit recovery and that creating more clones does not always improve qubit recovery.
The quantum internet, which will be a hybrid of quantum and classical networks, is expected to provide information-theoretic security for data transmission. Classical networks have well-established protocols for reliable end-to-end transmission that use duplicating the classical bits implicitly. However, due to the no-cloning theorem, quantum bits (qubits) cannot be copied. In this paper, we propose to use a Universal Quantum Copying Machine (UQCM) to create imperfect clones and summarizes the Quantum Automatic Repeat Request (QARQ) protocol, which is inspired by its classical counterpart. To investigate the viability of QARQ, a simulation platform is created considering Nitrogen-vacancy (NV) center qubit platform that implements QARQ for quantum communication. The results explore the applications it is suitable for while maintaining enough quality of the qubit state. Two major quantum technologies are studied for these protocols: Direct Transmission (DT), and Teleportation (TP). It has been shown that for short distance communication DT provides better fidelity than TP while for long-distance communication TP outperforms DT and hence improves the QARQ performance as well.
Quantum internet, which is expected to be a combination of quantum and classical networks, promises to provide information-theoretic security for data exchange. Classical networks have well-established protocols for reliable end-to-end transmission that implicitly make use of duplicating classical bits. However, quantum bits (qubits) cannot be copied due to the no-cloning theorem. In this paper, we take advantage of the principle of creating imperfect clones using a Universal Quantum Copying Machine (UQCM) and propose the Quantum Automatic Repeat Request (QARQ) protocol, inspired by its classical equivalent. A simulation platform has been developed to study the feasibility of QARQ. Results show that our proposal is well suited for applications that are compatible with low fidelity requirements.
Although perfect copying of an unknown quantum state is not possible, approximate cloning is possible in quantum mechanics. Quantum telecloning is a variant of approximate quantum cloning which uses quantum teleportation to allow for the use of classical communication to create physically separate clones of a quantum state. We present results of a of 1 →9 universal, symmetric, optimal quantum telecloning implementation on a cloud accessible quantum computer - the Quantinuum H1-1 device. The H1-1 device allows direct creation of the telecloning protocol due to real time classical if-statements that are conditional on the mid-circuit measurement outcome of a Bell measurement. In this implementation, we also provide an improvement over previous work for the circuit model description of quantum telecloning, which reduces the required gate depth and gate count for an all-to-all connectivity. The demonstration of creating 9 approximate clones on a quantum processor is the largest number of clones that has been generated, telecloning or otherwise.
Due to the no-cloning theorem, generating perfect quantum clones of an arbitrary unknown quantum state is not possible, however approximate quantum clones can be constructed. Quantum telecloning is a protocol that originates from a combination of quantum teleportation and quantum cloning. Here we present 1 → 2 and 1 → 3 quantum telecloning circuits, with and without ancilla, that are theoretically optimal (meaning the clones have the highest fidelity allowed by quantum mechanics), universal (meaning the clone fidelity is independent of the state being cloned), and symmetric (meaning the clones all have the same fidelity). We implement these circuits on gate model IBMQ and Quantinuum NISQ hardware and quantify the clone fidelities using parallel single qubit state tomography. Quantum telecloning using mid-circuit measurement with classical feed-forward control (i.e. real time if statements) is demonstrated on the Quantinuum H1-2 device. Two alternative implementations of quantum telecloning, deferred measurement and post selection, are demonstrated on ibmq_montreal, where mid-circuit measurements with real time if statements are not available. Our results show that NISQ devices can achieve near-optimal quantum telecloning fidelity; for example the Quantinuum H1-2 device running the telecloning circuits without ancilla achieved a mean clone fidelity of 0.824 with standard deviation of 0.024 for two clone circuits and 0.765 with standard deviation of 0.022 for three clone circuits. The theoretical fidelity limits are 0.83ˉ0.8\bar 30.83ˉ for two clones and 0.7ˉ0.\bar 70.7ˉ for three clones. This demonstrates the viability of performing experimental analysis of quantum information networks and quantum cryptography protocols on NISQ computers.
The no-cloning theorem provided a security feature that enabled the BB84 protocol to be a possible quantum protocol for secure key exchange. A possible method to undermine the security of the BB84 exists by utilizing a UQCM to imperfectly copy the qubits. However, due to the introduced errors, detections of an intruder using a UQCM is possible, in addition to the imperfect recovered key by the intruder. In this paper, a simulation of an intruder intercepting a 5 -qubit BB84 protocol execution with 1000 randomly generated sets of angles, 100 -time of BB84 simulation, for each set, is used to estimate the probability of detection and key recovery with a UQCM. Despite that a UQCM is universally optimized with the values on the 1998 paper of Vladimr R. Buzek and Mark Hillery, the simulations provided different values that can reduce the detection rate while increasing the probability of a successful key recovery. Moreover, there are multiple rotational angles that provides similar key recovery probability with varying degrees of discoverability.
Abstract No-cloning theorem forbids perfect cloning of an unknown quantum state. A universal quantum cloning machine (UQCM), capable of producing two copies of any input qubit with the optimal fidelity, is of fundamental interest and has applications in quantum information processing. This is enabled by delicately tailored nonclassical correlations between the input qubit and the copying qubits, which distinguish the UQCM from a classical counterpart, but whose experimental demonstrations are still lacking. We here implement the UQCM in a superconducting circuit and investigate these correlations. The measured entanglements well agree with our theoretical prediction that they are independent of the input state and thus constitute a universal quantum behavior of the UQCM that was not previously revealed. Another feature of our experiment is the realization of deterministic and individual cloning, in contrast to previously demonstrated UQCMs, which either were probabilistic or did not constitute true cloning of individual qubits.