IEEE Global Communications Conference
8–10 December 2020 // In-person (Taipei, Taiwan)
7-11 December 2020 // Virtual
Communications for Human and Machine Intelligence


Monday, December 7 14:00 - 14:15

WS-08_K1: Welcome to QCIT'20

Chair: Lajos Hanzo


Monday, December 7 14:15 - 14:45

WS-08-K2: QCIT'20 Keynote

Chair: Peter Mueller

Quantum Secure Direct Communication: Current Status and Perspective Application in Network
Gui-Lu Long, Tsinghua University and Beijing Academy of Quantum Information Sciences

Quantum secure direct communication (QSDC) transmits information directly over a quantum channel. Over the last few years, tremendous progress has been made. Detailed security analysis, coding schemes for high loss quantum channel and quantum-memory-free protocols have been developed. A practical QSDC prototype that supports texts, image files and real-time telephone has been implemented. Recently, it has been proposed that by combining QSDC with post-quantum cryptographic algorithms, secure-repeater quantum networks can be built that offers secure end-to-end communication, eavesdropping detecting capability and fully compatibility with existing network.


Monday, December 7 14:45 - 15:30

WS-08-S1: Quantum Communications and Information Technology I

Chair: Andrea Conti

Multi-mode CV-QKD with Noiseless Attenuation and Amplification
Mingjian He, Robert Malaney and Benjamin Burnett

In this work we study the use of noiseless attenuation and noiseless amplification, in terms of multi-mode Continuous-Variable (CV) Quantum Key Distribution (QKD) over satellite-to-ground channels. We propose an improved multi-mode CV-QKD protocol where noiseless attenuation and noiseless amplification operations are applied at the transmitter and the receiver, respectively. Our results show that consistent with single-mode CV-QKD, the noiseless amplification operation, when applied at the receiver, can increase the transmission distance and the channel noise tolerance of multi-mode CV-QKD. Different from single-mode CV-QKD, in multi-mode CV-QKD the key rate improvement offered by noiseless amplification can be further enhanced by adding noiseless attenuation at the transmitter.


Quantum DevOps: Towards Reliable and Applicable NISQ Quantum Computing
Ilie Daniel Gheorghe Pop, Nikolay Tcholtchev, Manfred Hauswirth and Tom Ritter

Quantum Computing is emerging as one of the great hopes for boosting current computational resources and enabling the application of ICT for optimizing processes and solving complex and challenging domain specific problems. However, the Quantum Computing technology has not matured to a level yet, where it can provide a clear advantage over high performance computing. In order to achieve this "quantum advantage", a larger number of Qubits is required that inevitably leads to a more complex topology of the computing Qubits, which incurs additional problems with de-coherence times and implies higher Qubit error rates. Nevertheless, the current Noisy Intermediate-Scale Quantum (NISQ) computers can prove useful despite the intrinsic uncertainties on the quantum hardware layer. In order to utilize such error-prone computing resources, various concepts are required to address Qubit errors and to deliver successful computations. In this paper we motivate the need for and describe the novel concept of Quantum DevOps, which enables regular checking of the reliability of NISQ Quantum Computing (QC) instances by testing the computational reliability of basic quantum gates and computations (C-NOT, Hadamard, etc.), thereby estimating the likelihood for a large scale critical computation (e.g. calculating hourly traffic flow models for a city) to provide results of sufficient quality. This approach can be used to select the best matching (cloud) QC instance and should be integrated directly with the processes of development, testing and finally the operations of quantum based algorithms and systems, thereby enabling the Quantum DevOps concept.


Monday, December 7 15:30 - 16:00

Coffee break


Monday, December 7 16:00 - 17:30

WS-08-S2: Quantum Communications and Information Technology II

Chair: Soon Xin Ng

Refined Belief-Propagation Decoding of Quantum Codes with Scalar Messages
Kao-Yueh Kuo and Ching-Yi Lai

Codes based on sparse matrices have good performance and can be efficiently decoded by belief-propagation (BP). Decoding binary stabilizer codes needs a quaternary BP for (additive) codes over GF(4), which has a higher check-node complexity compared to a binary BP for codes over GF(2). Moreover, BP decoding of stabilizer codes suffers a performance loss from the short cycles in the underlying Tanner graph. In this paper, we propose a refined BP algorithm for decoding quantum codes by passing scalar messages. For a given error syndrome, this algorithm decodes to the same output as the conventional quaternary BP but has a check-node complexity the same as binary BP. As every message is a scalar, the message normalization can be naturally applied to improve the performance. Another observation is that the message-update schedule affects the BP decoding performance against short cycles. We show that running BP with message normalization according to a serial schedule (or other schedules) may significantly improve the decoding performance and error floor in computer simulation.


Quantum Pulse Position Modulation with Photon-Added Squeezed States
Stefano Guerrini, Marco Chiani, Moe Z. Win and Andrea Conti

This paper introduces the use of photon-added squeezed states (PASSs) for quantum pulse position modulation (QPPM). It is shown that the use of PASSs in QPPM communication systems can reduce the symbol error probability (SEP) with respect to the use of different classes of quantum states with the same energy, including squeezed states and photon-added coherent states. The impact of thermal noise and phase diffusion on the SEP is also evaluated. The findings of this paper show the utility of PASSs in quantum communication systems.


Solving the Minimum Spanning Tree Problem with a Quantum Annealer
Wesley O'Quinn and Shiwen Mao

Quantum annealing (QA) is a different technology than gate-model quantum computation. This research proposes a novel technique for solving the Minimum Spanning Tree (MST) problem on a quantum annealer. This problem is of interest due to its applications in clustering, unsupervised learning, network design, and image processing to name a few. The advent of quantum cloud computing has provided access to quantum computing tools, previously unavailable to the general community. D-Wave systems recently released cloud access to their quantum annealer type hardware, which this project leverages to provide a novel solution method to the MST problem.


OpenSurgery for Topological Assemblies
Alexandru Paler and Austin Fowler

Surface quantum error-correcting codes are the leading proposal for fault-tolerance within quantum computers. We present OpenSurgery, a scalable tool for the preparation of circuits protected by the surface code operated through lattice surgery. Lattice surgery is considered a resource efficient method to implement surface code computations. Resource efficiency refers to the number of physical qubits and the time necessary for executing a quantum computation. OpenSurgery is a first step towards methods that aid quantum algorithm design informed by the realities of the hardware architectures. OpenSurgery can: 1) lay out arbitrary quantum circuits, 2) estimate the quantum resources used for their execution, 3) visualise the resulting 3D topological assemblies. Source code is available at \url{}.