CS 598QC: Frontiers of Quantum Complexity
(Spring 2024)

Course Information

Instructor: Makrand Sinha (msinha@illinois.edu)

Credits: 4

Time: Mondays and Wednesdays 2:00 - 3:15 pm

Location: 1302 Siebel Center

Office Hours: after class or by appointment

Discussion Forum: Ed Discussion. You will automatically be enrolled based on your @illinois.edu email. All course announcements, policies, discussions and homeworks will be available only on Ed Discussion. Instead of sending emails, students are encouraged to send direct messages to the course staff via the chat feature on Ed Discussion. If you sign up late, please send an email to msinha@illinois.edu to be enrolled in Ed Discussion and Gradescope.

Homework Submission: Gradescope

Class Recordings: Mediaspace (UIUC restricted)

Course Description

This is an advanced, PhD-level topics class in quantum complexity theory — the study of the fundamental capabilities and limitations of quantum computers. The course will explore four different themes:


The goal is to explore the results and (more importantly) the questions in this field to bring the students to the research frontier. A highly-tentative list of topics includes:

Prerequisites

The key prerequisite for this course is mathematical maturity. During this course, we will touch upon fairly advanced topics that incoporate ideas from diverse mathematical fields. Having taken a few 400 or 500 level (proof-based) math or theoretical computer science courses is strongly recommended. While we will quickly cover the necessary quantum computing and complexity background, some familiarity with classical complexity classes (P, NP) and basic quantum computing is beneficial. Those without sufficient background are recommended to work on supplementary material to internalize the ideas.

Tentative Schedule (subject to changes)

Date Topic Notes Additional Resources
Jan 17 Course Overview, Quantum Information Refresher Introduction,
Quantum Refresher
Quantum Information Fundamentals
Jan 22 Quantum Information Refresher (contd), Complexity Basics Complexity Basics Chapters 1 and 2 in Arora-Barak textbook
Jan 24 BQP and its properties Notes Quantum Complexity Theory by Ethan Bernstein and Umesh Vazirani
Jan 29 BQP and its properties (contd) Notes
Jan 31 Oracles, BQP vs BPP Notes Chapter 3 in Ronald de Wolf's lecture notes
Feb 5 Oracle Separation, BQP vs NP Notes Chapter 7 in Ronald de Wolf's lecture notes
Feb 7 Quantum Lower Bounds via Polynomials Notes Survey on Approximate Degree
Feb 12 BQP vs PH (part 1) Notes Oracle Separation of BQP and PH by Ran Raz and Avishay Tal
Feb 14 BQP vs PH (part 2) Notes
Feb 19 Quantum Speedups and Structure,
Separation of BQP and BPP with Search problems
Notes The Need for Structure in Quantum Speedups by Scott Aaronson and Andris Ambainis
Verifiable Quantum Advantage without Structure by Takashi Yamakawa and Mark Zhandry
Feb 21 Separation of BQP and BPP with Search problems (contd) Notes
Feb 26 Near-term Quantum Advantage Notes Paper on Random Circuit Sampling by Adam Bouland, Bill Fefferman, Chinmay Nirkhe and Umesh Vazirani
Feb 28 Near-term Quantum Advantage (contd), QMA and its properties Notes
Mar 4 Properties of QMA, Error Reduction in QMA Notes
Mar 6 Witness-preserving QMA Error Reduction Notes Quantum Arthur-Merlin Games by Chris Marriott and John Watrous
Mar 11 Spring Break
Mar 13 Spring Break
Mar 18 Local Hamiltonian Problem Notes
Mar 20 Local Hamiltonian Problem (contd), QMA(2) Notes
Mar 25 Short QMA(2) proofs for NP Notes A quantum characterization of NP by Hugue Blier and Alain Tapp
Mar 27 QMA(2) and Detecting Entanglement, Complexity of Ground States Notes
Apr 1 Quantum PCP Conjecture Notes Survey on the Quantum PCP Conjecture by Dorit Aharonov, Itai Arad and Thomas Vidick
Apr 3 Tensor Networks and Matrix Product States Notes Hand-waving and Interpretive Dance: An Introductory Course on Tensor Networks by Jacob Bridgeman and Christopher Chubb
Apr 8 No class
Apr 10 Area Laws Notes Lecture Notes from a course by Thomas Vidick
Apr 15 Area Laws (contd), State Synthesis Notes
Apr 17 State and Unitary Synthesis Notes A one-query lower bound for unitary synthesis and breaking quantum cryptography by Alex Lombardi, Fermi Ma and John Wright
Apr 22 Unitary Synthesis Lower Bound
Pseudorandom States and Designs
Notes Pseudorandom States, Non-Cloning Theorems and Quantum Money by Zhengfeng Ji, Yi-Kai Liu and Fang Song
Apr 24 Applications and Constructions of Pseudorandom States and State Designs Notes (Pseudo) Random Quantum States with Binary Phase by Zvika Brakerski and Omri Shmueli
Apr 29 Pseudorandom States (contd)
Pseudorandom Unitaries and Unitary Designs
Notes Simple constructions of linear-depth t-designs and pseudorandom unitaries by Tony Metger, Alexander Poremba, Makrand Sinha and Henry Yuen
May 1 Jeopardy

Additional Resources for Prerequisites

Grading Policy