# SUPERCONDUCTING QUANTUM PROCESSORS - 2024/5

Module code: PHYM068

## Module Overview

Quantum computers are built around a central processing unit which is a physical device operating according to the rules of quantum mechanics. This module teaches the principles of how quantum processors are built and how they function. The module follows the superconducting architecture, which currently has a significant role in the industry and has been widely studied and implemented. The module will start with reviewing the basic physics required to understand superconducting qubits and the theory of superconducting circuits. It will then continue to the operation of such qubits to perform gates, storage, and readout. After studying the basic building blocks and operations, the module will discuss early demonstrations of important algorithms on superconducting processors. These will lead us naturally to the important topics of improving performance through protection of coherence, advanced control, and validation. The last part of the module will focus on state-of-the-art superconducting processors, focusing on the various challenges in scaling up and the strategies that the industry is pursuing to overcome them.

### Module provider

Mathematics & Physics

GINOSSAR Eran (Maths & Phys)

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

Independent Learning Hours: 55

Lecture Hours: 22

Tutorial Hours: 11

Guided Learning: 40

Captured Content: 22

Semester 1

N/A

## Module content

Superconductivity and the Josephson effect.

What are superconductors and what are their electrical and electromagnetic properties. This is a brief introduction to the topic which enable us to discuss the Josephson junction as an electrical circuit component essential for the design and realisation of all superconducting qubits.

Classical electrodynamics of superconducting circuits.

Here we learn about the circuit theory which underlies the superconducting quantum processor. These processors are electrical circuits which have truly little loss since they operate as superconductors at extremely low temperatures. Their operating frequency is high, in the microwave range, and here we focus on their electrical properties and how to perform basic circuit analysis.

Quantum theory of superconducting resonators and qubits

Now we can discuss how to describe the superconducting circuit in the quantum regime and how qubits and quantum resonators arise. These are the basic elements that quantum processors are built from.

Quantum information processing with superconducting circuits

Here we can put together all the elements and discuss the dynamical processes which happen for initialising the qubits’ quantum state, how to perform single and two qubit gates, and how to read out the quantum state information.

Performance and validation of superconducting qubits.

Here we will learn about how realistic qubits are not perfect i.e., there are various physical processes which introduce errors in the control and retention of quantum information. We will discuss how the performance of qubit gates is assessed and which strategies we can take to mitigate these issues.

Large scale quantum processors.

Here we explore the architecture of quantum processors which contain many qubits. We discuss how the hardware architecture supports different quantum computing paradigms. We also discuss the design and engineering challenges and the strategies which are currently being pursued.

Equality, Diversity and Inclusion.

As part of our commitment to the values of the Department, an equality, diversity and inclusion awareness workshop will be held.

## Assessment pattern

Assessment type Unit of assessment Weighting
Online Scheduled Summative Class Test EDI awareness Pass/Fail
Coursework Problem sheets 30
Examination Exam (2 hours) 70

N/A

## Assessment Strategy

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

• in-depth understanding of superconducting quantum processors and demonstrate considerable and continuous engagement with the topic. The following activities will appear in the different parts of the assessment. They will recall and apply basic superconducting circuit theory. The student will demonstrate understanding of operating principles that govern basic superconducting qubit designs and the various trade-offs which arise when considering the protection of quantum information vs. qubit performance. They will be able to perform relevant calculations demonstrating these considerations. They will demonstrate understanding of the methods for performance validation and error mitigation. They will be demonstrating knowledge of large-scale quantum processor design considerations, challenges, and strategies for scaling up.

• analytical ability by solution of unseen problems in both coursework and exam

• subject knowledge by recall of both “textbook” theory and important research articles in the exam

• ability to generalize text-book theory by open-ended research component in the coursework.

Thus, the summative assessment for this module consists of:

• The assessment of engagement with the EDI Awareness Workshop will be by an open book quiz with unlimited re-attempts, but it must be passed in order to pass the module. (Learning outcome 9).

• Coursework: consists of a set of problems, Learning Objectives 1-8.

• An exam comprising a Part A in which all questions are compulsory (to assess breadth) and a Part B in which students must answer two questions out of three (to assess depth), Learning Objectives 1-8.

Formative assessment:

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

Feedback:

• Students are asked to attempt problem solving during tutorials and receive immediate feedback from tutors. They also receive written feedback on formative assessments.

## Module aims

• This module aims to introduce the architecture of superconducting circuits, with the relevant physical background in electrodynamics and superconductivity. Building on these, the module continues to describe how quantum information processing is achieved with superconducting qubits and how these building blocks are validated and scaled up to become quantum processors.

## Learning outcomes

 Attributes Developed 001 Describe the phenomenon of superconductivity and Josephson effect. KCP 002 Exhibit an understanding of superconducting circuits (classical). KCP 003 Apply the principles of circuit theory to basic circuits. KCP 004 Exhibit understanding of superconducting qubits. KCP 005 Demonstrate knowledge and understanding of quantum information processing methods. KCP 006 Describe how the performance of gates is assessed. KCP 007 Exhibit an understanding of optimal control and error mitigation methods. KCPT 008 Demonstrate knowledge and understanding of quantum processor architecture and the issues around scalability. KC 009 Awareness of Equality, Diversity and Inclusion. PT

Attributes Developed

C - Cognitive/analytical

K - Subject knowledge

T - Transferable skills

P - Professional/Practical skills

## Methods of Teaching / Learning

The learning and teaching strategy is designed to:

• a comprehensive theoretical treatment for the subject knowledge.

• practice in problem solving for the cognitive skills.

Thus the learning and teaching methods include:

• “chalk and talk” lectures backed up with a guided study to stimulate uptake of subject knowledge in lectures.

• tutorial demonstration of solutions to key problems after students have attempted them for formative feedback.

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.

Upon accessing the reading list, please search for the module using the module code: PHYM068

## Other information

Global and Cultural Capabilities The module includes an Equality, Diversity and Inclusivity (EDI) workshop which aims to increase awareness of cultural, religious, or racial differences while delivering information about how a person can change their behavior to be more inclusive. Through this training, students are encouraged to diversify their knowledge and reflect upon their experiences as a physicist and in education.

Digital Capabilities: Students will gain expertise in analysing electrical circuits and working with cutting edge software packages for analysis and simulation.

Employability: The students will gain in-depth knowledge in a quantum computing platform that is now a basis of a growing high-tech industry.

Resourcefulness and Resilience: The self-reflection coursework will allow students to demonstrate self-reliance and ability to take charge of their own education strategy, and their approach to remedying weakness and to attain strength.

## Programmes this module appears in

Programme Semester Classification Qualifying conditions
Applied Quantum Computing MSc 1 Compulsory A weighted aggregate mark of 50% is required to pass the module

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.