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Quantum Communication Networks 

Kvantumhálózatok
A tantárgyleírás hatályossága
Hatályosság kezdete:
2026. March 21.
Hatályosság vége:
Subject name (Hungarian, English)
Kvantumhálózatok
Quantum Communication Networks 
Subject code BMEVIHIMA25
Subject type
Training Level
Course types and hours (weekly/semester)
Course type lecture tutorial laboratory
hours (weekly) 2 1 0
type (linked/independent) derived course
Assessment type vizsga
Credits 5
Subject coordinator
DR. Bacsárdi László
position: egyetemi docens
Responsible department
Hálózati Rendszerek és Szolgáltatások Tanszék
Faculty Villamosmérnöki és Informatikai Kar
Subject website
Primary curriculum type
Direct prerequisites – Strong prerequisite none
Direct prerequisites – Weak prerequisite none
Direct prerequisites – Parallel prerequisite none
Direct prerequisites – Milestone prerequisite none
Direct prerequisites – Exclusion none

Objectives

Programme
Detailed descriptions of lectures
1.    Operating model of quantum communication networks, application areas.
2.    Basic concepts of quantum information theory. Density matrix notation in quantum information science. Postulates with density matrix. Pure and mixed states.
3.    Simple quantum communication protocols: teleportation, superdense compression.
4.     Basic protocols for quantum key distribution. Prepare-and-measure and entanglement-based QKD
5.    Above the physical layer of QKD: information reconcelation and privacy amplification
6.    Design issues for long-range quantum key distribution systems. ETSI QKD standards.
7.    Concepts of quantum entropy, conditional quantum entropy, mutual quantum information, quantum-relative entropy function, analogy with classical systems. Description and characterization of quantum channels. Fundamental quantum channels. Classical and quantum capacitance definitions. Holevo theorem. Definition of capacitances for typical quantum channels. 
8.    Error correction of quantum channels, related information theoretic constraints. Overview of error correcting encodings, efficiency, discussion of physical implementations.
9.    Quantum Internet architecture and protocols
10.    The principle of quantum repeaters and their applications in telecommunication systems. Physical architecture of quantum memory and quantum repeaters
11.    Convergence sharing protocol and its applications. Communication on zero capacity channel, superactivation
12.    Technological challenges of optical fiber quantum communication systems
13.    Technological challenges of outdoor and satellite quantum communication systems
14.    Summary of the semester. Outlook: market and future of quantum networks

Detailed topics of the exercises/lab
1.    Application of a density matrix notation system.
2.    Quantum key distribution network design in practice.
3.    Prepare-and-measure quantum key distribution in practice.
4.    Entanglement-based quantum key distribution in practice.
5.    Quantum Internet protocols.
6.    Entanglement sharing through examples.
7.    Next generation quantum key distribution architectures.

The objective of the course is to provide students with knowledge of quantum communication. The aim of the course is to explain the fundamentals of quantum communication networks and to explain the importance of quantum communication and the diversity of its applications. Following an introduction to the basic concepts of related quantum information theory, the course will provide a thorough overview of quantum communication networks, covering both quantum key distribution (QKD) networks and the so-called ‘beyond QKD’ solutions that are the basis of the future quantum Internet.

Learning outcomes

Ez a tantárgy a KKK rendeletben meghatározott, következő kompetenciák fejlesztését szolgálja:

Knowledge

No learning outcomes recorded.

Skills

No learning outcomes recorded.

Attitudes

No learning outcomes recorded.

Autonomy and responsibility

No learning outcomes recorded.

Oktatási módszertan

Lecture. Successful completion of the subject and the interdependence of knowledge require to continuous follow the content of the lectures.   Practice: review of lecture material, supplemented by practical examples

Tanulástámogató anyagok

Online források
1. S. Imre, L. Gyöngyösi: Advanced Quantum Communications - An Engineering Approach, Publisher: Wiley-IEEE Press (New Jersey, USA), John Wiley & Sons, Inc., 2012; Additional Hungarian and English language resources are available in electronic form.

Recommended preliminary knowledge for completing the subject

Knowledge type competencies
(azon előzetes ismeretek összessége, amelyek megléte nem kötelező, de a tantárgy eredményes teljesítését nagyban elősegíti)
probability, linear algebra
Skill type competencies
(azon előzetes képességek és készségek összessége, amelyek megléte nem kötelező, de a tantárgy eredményes teljesítését nagyban elősegíti)
nincs
Recommended (non-compulsory) preliminary competencies
(azon ajánlott (nem kötelező) előzetesen megszerzendő kompetenciák összessége, amelyek jelentősen hozzájárulnak a tantárgy eredményes teljesítéséhez)
probability, linear algebra
General rules
Requirements: During the semester, students write 1 mid-term exam and 2 small homework assignments. The criteria for the successful semester: minimum of 40% of the score of the mid-term exam AND minimum of 40% of the total score of the two small assignments. Oral exam Additional possibilities: Students will be given the opportunity to retake the mid-term exam during the retake week. Late submission of the two small homework assignments is possible until the fourth day of the retake week for a special fee.
Assessment methods
In-term assessments

No detailed assessments provided.

Weight of in-term assessments

No weights provided.

Exam-period assessments

No detailed assessments provided.

Weight of exam elements

No weights provided.

Grade calculation

No grade thresholds provided.

Attendance requirements

No attendance requirements provided.

Rules for retake and resubmission

Not provided.

Short description

Not provided.

Detailed description

Not provided.

Recommended courses

Not provided.

Workload to complete the subject

No workload breakdown provided.

Validity of subject requirements
Requirements valid from:
Requirements valid until:
Curriculum placement

No curriculum placements recorded for this subject version.