APPLIED QUANTUM COMPUTING II (QUANTUM COMMUNICATIONS AND QUANTUM ENTANGLEMENT AND COHERENCE) - 2024/5

Module Overview

This module comprises two independent halves, on Quantum Communications plus Quantum Entanglement and Quantum Coherence.

• Quantum communications. This course provides a comprehensive introduction to the principles, protocols, and applications of quantum communications. Students will explore the fundamental concepts of quantum information transmission, quantum cryptography, and quantum communication protocols. They will also examine the challenges, advancements, and real-world applications of quantum communications including both theory and practical aspects.


• Quantum Entanglement and Quantum Coherence. An understanding of the formalism and mathematical framework of quantum theory is vital on such a course, but while other modules and half modules will introduce the basic theoretical background (operators, Hilbert space, eigenstates, Dirac notation, quantum spin, the Schrödinger Equation, Hamiltonians, commutation relations etc), they will all likely deal with isolated quantum systems. The basis of quantum computing requires an understanding of the important concepts of entanglement and decoherence, which in turn require an understanding of open quantum systems and the density matrix formalism. These topics are not typically covered in undergraduate physics courses. This module requires some understanding of the basic formalism of QM, either as courses taught in undergraduate physics degrees or, for students on the course who have not encountered much or any QM in their u/g degree, to have taken the module Introduction to Quantum Computing. While the mathematics involved in this half module is not too advanced, students will need to have some basic familiarity with Dirac notation (Bra-Ket notation).

Module provider

Mathematics & Physics

Module Leader

FLORESCU Marian (Maths & Phys)

Number of Credits: 15

ECTS Credits: 7.5

Framework: FHEQ Level 7

Module cap (Maximum number of students): N/A

Module Availability

Semester 2

Prerequisites / Co-requisites

N/A

Module content

Indicative content for the Quantum Communications part:

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    • Classical cryptography and introduction to quantum communications. We first need to discuss classical encryption strategies, like RSA (which is the standard used in most secure communications), and how these strategies might be attacked. The idea of a one-time-pad as an encryption key makes communication totally secure, but the keys must first be generated totally randomly (which can be performed with quantum dice), and then transmitted totally securely. The BB84 protocol for quantum key distirbution is the simplest to explain and makes a neat introduction to quantum cryptography.
    
    
    • Entanglement as a resource for communications. The quantum nature of light gives an advantage for the transmission of information, which allows much more information to be transmitted than 1 bit per photon sent (superdense coding). This advantage relies on having prepared a resource called an entangled pair (of photons or spins etc), where one of the pair is held by each of the two people wanting to communicate (who are usually referred to as Alice and Bob). Entangled resource can also be used to teleport quantum information from Alice to Bob in an extremely efficient way: Bob can get an exact copy of Alice’s qubit if she only tells him two classical bits (an otherwise impossible feat since Alice’s qubit encodes two arbitrary complex numbers)!
    
    
    • Entanglement and quantum cryptography. For long distance quantum key distribution, repeater stages are needed, just like the amplifier stages in classical optical fibre networks. Strategies for secure quantum communication via repeaters rely on entangled photon pairs, and here we will investigate modern cryptography systems, including via fibres and satellites.
    
    
    • Hardware. Although the module is primarily about the algorithms for quantum communications, hardware is always the limiting factor in quantum technology, so we will investigate the state of development and future prospects.
    
    
    • Latest research. The latest research will be used to inform content in both the communications protocols and hardware.
    
    
    
    
  
  
  
  

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    • Introduction. The course starts off assuming the students have been introduced to the ideas of superposition in QM and are familiar with Dirac bra-ket notation to describe quantum states. There will be a general introduction and revision of the idea of orthonormal bases and complete sets of eigenstates, the idea of spin, spin operators and eigenstates and the Bloch sphere.
    
    
    • Density matrix. Next, the students move on to the idea of entanglement and Bell states and what it means for such states to decohere when they interact with their environment. It is explained that the best way to deal with this is through the use of the so-called density matrix instead of the quantum state as ket (or a wave function). Various derivations and exercises will be covered in the lectures, such as how to take the trace of the density matrix, its relation to expectation values of observables in QM and the derivation of the reduced density matrix.
    
    
    • The Measurement Problem and decoherence. The famous measurement problem is central in quantum computing and we examine it through the modern lens of the density matrix approach and open quantum systems. Quantum decoherence is examined carefully and contrasted with the classical notions of dissipation and noise.
    
    
    • Master equations. Students are introduced to different types, such as those using the Born-Markov approximation, the Lindblad form, the quantum Brownian motion model of Caldeira and Leggett and finally non-Markovian approaches.
    
    
    
    
  
  
  
  

Assessment pattern

Alternative Assessment

In situations where the Q Comms Project (Group part) requires an alternative or reassessment it will be replaced with an individual literature review.

Assessment Strategy

The assessment strategy is designed to provide you with the opportunity to demonstrate:

• both individual knowledge and results of team contributions to group outcomes. (Q Comms).


• problem-solving abilities. (Q Comms and QEQC).


• adaptability, collaboration skills resulting in team contributions to group outcomes (Q Comms).

• The Q Comms Project assessment (Learning Objectives 1-3) will take the form of a team activity for the production of the combination of a literature review, computation/modelling assessment of the likely reliability of communication systems built with the technology reviewed, presentation and peer assessment. There will be an element of choice over the combination of activities/roles undertaken (e.g. in order to take account of your English language fluency and neurodiversity needs). Within this Project there are Group and Individual components.
  
  
  
  
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      • group-authored technical report (7 pages max) on quantum communications applications and implementation 
      
      
      • individual presentation presentation on the quantum communication project (10 mins max)
      
      
      
      
    
    
    
    
  
  
  
  


• The QEQC exam addressing Learning Outcomes: 4-7.

• Formative Feedback and Coaching will be provided that is timely and constructive throughout the project duration to guide Q Comms project groups in their implementation. (Q Comms)


• A team project Proposal and Plan, will be submitted early in the Q Comms project for formative assessment, outlining the objectives for each individual (i.e. with different tasks for each member of the team), a scope, methodology, and timeline. [Assessed on the clarity, feasibility, and appropriateness of the methodology, techniques and tools.] (Q Comms).


• As preparation for the exam, tutorials will include examples of exam-style and/or past paper questions, followed later by model solutions. (QEQC).

• Verbal feedback will be given in tutorials. (Q Comms and QEQC).


• One-to-one advice in open office hours (Q Comms).

Module aims

• Explain the fundamental principles of quantum communications and analyze various quantum cryptography protocols, such as quantum key distribution (QKD) schemes (Q Comm).
• Explore the practical challenges and advancements in quantum channel modeling, noise analysis, and error/eavesdropper detection (Q Comm).
• Critically evaluate and discuss the ethical and societal implications of quantum communications and quantum technology more widely (Q Comm).
• Introduction to the concept of a density matrix to describe quantum states (pure and mixed) (QEQC).
• Introducing the concept of quantum entanglement as a general and fundamental feature of the quantum world and not necessarily only with applications in QC (QEQC).
• To explain the process of decoherence that is the central challenge in QC (QEQC).
• To give a general introduction to open quantum systems and master equations (QEQC).
• To touch on foundational problems in QM such as the notion of measurement and observers (QEQC).

Learning outcomes

Methods of Teaching / Learning

The learning and teaching strategy is designed to:

• Enable students to gain knowledge of the topic of quantum communications in an interactive way, encouraging them to solve problems rather than learn by rote (Q Comms).


• Enhance students’ group collaboration and presentation skills (Q Comms).


• Give students experience of working in a trusted environment where they can develop their own strategies for learning and self-improvement. (Q Comms).


• An introduction to the theoretical ideas behind concepts such as quantum entanglement and decoherence that are central to quantum computing (QEQC).


• practice in problem solving to develop the cognitive skills (QEQC).

• A combination of traditional lectures backed up with guided study to stimulate uptake of subject knowledge (Q Comms and QEQC).


• tutorial demonstration of solutions to key problems, with practice for students both before and after having attempted them for formative feedback (Q Comms and QEQC).


• peer learning and teaching with structured Surrey-Learn hosted discussion boards focussed on the above (Q Comms and QEQC).


• Workshops for group activities (Q Comms).

Indicated Lecture Hours (which may also include seminars, tutorials, workshops and other contact time) are approximate and may include in-class tests where one or more of these are an assessment on the module. In-class tests are scheduled/organised separately to taught content and will be published on to student personal timetables, where they apply to taken modules, as soon as they are finalised by central administration. This will usually be after the initial publication of the teaching timetable for the relevant semester.

Reading list

https://readinglists.surrey.ac.uk
Upon accessing the reading list, please search for the module using the module code: PHYM069

Other information

Digital Capabilities: In this module we study a revolution in digital capabilities: the quantum computer, and the corresponding advantages for communications (Q Comms). Students are also introduced to the quantum concepts and mathematical formalism necessary to be able to understand the digital capabilities of quantum computers (QEQC).

Global and Cultural Capabilities: Quantum computing and communications raises ethical questions to which the answers must come from a diverse set of cultures. For example, if quantum computing can be used for drug discovery, then bad actors could use it for bio-chemical weapons discovery. Quantum communications could allow information security for the wealthy but not ordinary citizens. We will encourage students to critically analyse how quantum computing and communications can impact individual rights, privacy, fairness, and accountability from a global perspective. Understanding and appreciating diverse ethical viewpoints can enhance students' cultural sensitivity and help them navigate the complex and very new ethical landscape produced by quantum computing in a global context (Q Comms).

Resourcefulness and Resilience: By participating in group activities, students have the opportunity to demonstrate resourcefulness and resilience through problem-solving, time management, collaboration, conflict resolution, adaptability, seeking feedback, and reflective practices. These skills are invaluable in navigating challenges, both within group settings and in real-world situations, fostering their personal growth and success (Q Comms). Conversely, by working independently through the questions set in the tutorial sheets and then checking their solutions against the model answers provided, students will develop the confidence and resilience to tackle and solve problems in the subject of quantum entanglement and decoherence as it applies in quantum computing (QEQC).

Employability. The group project will enhance students' employability by providing them with practical experience in collaboration, communication, problem-solving, adaptability, accountability to others, time management, leadership, professionalism, and networking. These skills are transferable to various professional settings and contribute to their readiness for the workforce (Q Comms).

Please note that the information detailed within this record is accurate at the time of publishing and may be subject to change. This record contains information for the most up to date version of the programme / module for the 2024/5 academic year.