Proceedings

EPJ D Highlight - Approximate quantum cloning: the new way of eavesdropping in quantum cryptography

New approximate cloning method facilitates quantum computing. Credit Markus Spiske via Unsplash.

New approximate cloning method avoids the previous limitations of quantum cloning to enhance quantum computing and quantum cryptography leaks

Cloning of quantum states is used for eavesdropping in quantum cryptography. It also has applications in quantum computation based on quantum information distribution. Uncertainty at the quantum scale makes exact cloning of quantum states impossible. Yet, they may be copied in an approximate way - with a certain level of probability - using a method called probabilistic quantum cloning, or PQC. In a new study published in EPJ D, Pinshu Rui from Anhui Xinhua and Anhui Universities, based in Hefei, China, and colleagues demonstrate that partial PQC of a given quantum state secretly chosen from a certain set of states, which can be expressed as the superposition of the other states, is possible.

This study is an extension of previous PQC work by Duan and Guo, dating back to 1998, which showed that quantum states can only be probabilistically cloned if all the states in the set are independent - i.e. they cannot be expressed as the linear superposition of the other states. Here, the authors show that if - and only if - an independent subset cannot be expressed as the superposition of the other states in the set, then these dependent states can be partially cloned.

As part of this study, the authors then establish the optimal cloning efficiencies for their approach.

This cloning operation is very important with regard to classical computing. It allows scientists to make many copies of the output of computations - which take the form of unitary operations. These can, in turn, be used as input and fed into various further processes. In quantum computing, for example, previous studies have shown that PQC can help to enhance performance compared to alternative methods. This means that when unitary operations generate some linearly-dependent states, partial PQC can be helpful.

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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