QIC 890 / CS 867 / CO 781/486 :

Quantum Error Correction and Fault Tolerance, Winter 2024


Instructors:

Debbie Leung

Email: wcleung(at)uwaterloo(dot)ca

Michael Vasmer

Email: mvasmer(at)perimeterinstitute(dot)ca

TA:

Kohdai Kuroiwa

Email: kkuroiwa(at)uwaterloo(dot)ca

Lectures:

Thur 10:00-12:50, QNC 1201

10 lectures in Jan 11 - Mar 21

Full play list for recordings

Term project presentations Apr 01-05, to be held at this zoom link

Discussions:

Instructors: after class or by appointment

TA office hour: dynamically decided

Piazza: (Sign up here or email Debbie for invitation)

Assessments:

5 assignments (total 75%)

Term project (25%)

Announcements:


Course description:


Students will learn:

(1) Principles for quantum error correction

(2) Stabilizer formalism

(3) Important classes of quantum error correcting codes

(4) Fault-tolerant quantum computation and the threshold theorem

(5) Select applications of QECC


Course materials


Resources:

  • Prerequisite: QIC 710
  • QECC notes from CO481 W2019
  • Textbook by Nielsen and Chuang
  • Daniel Gottesman's PhD thesis
  • John Preskill Lecture notes for Physics 229
  • Website for W2018 offering
  • Website for W2022 offering
  • Syllabus:

    Lectures 1-2: Basics of quantum noise and quantum error correction
  • Quantum operations and channels
  • Independence and low weight errors
  • The 9-bit Shor code
  • Discretization of quantum errors
  • Quantum error correction criterion
  • Degenerate and non-degenerate codes
  • Notes 1 Notes 2 Supp notes

    Lecture 1 recording

    Lectures 2-3: Stabilizer codes
  • Classical linear codes
  • Pauli group
  • Symplectic representation
  • Stabilizer codes
  • CSS codes
  • Erasure codes
  • Notes 1 Notes 2 Notes 3

    Lecture 2 recording

    Lecture 3 recording (missing last 30 mins on Notes 3, on erasures)

    A1, due Feb 02, 7pm on Crowdmark

    Lecture 4: Evolution under the stabilizer framework
  • Clifford group
  • Group action on Pauli group
  • Encoded operations
  • Measurements
  • Gottesman-Knill Theorem
  • Gate teleportation
  • Ck hierachy
  • Notes 1

    Lecture 4 recording (covering Notes 1, missing p3-8)

    Covered in lecture 6: Notes 2 Bacon-Shor-code example References

    A2, due Feb 23, 7pm on Crowdmark

    Lecture 5: Quantum LDPC codes (I)

  • Linear codes revisited - Tanner graph representation
  • Classical low-density parity-check (LDPC) codes
  • Hypergraph product codes
  • Properties of hypergraph product codes (stabilizer weight)
  • Toric code as a hypergraph product of two classical repetition codes
  • Notes 1 Notes 2

    Lecture 5 recording

    Lecture 6: Toric code
  • Definition as stabilizer code in lattice picture
  • Code parameters
  • Syndromes as excitations
  • Decoding algorithms
  • Distance vs other measures of error correction capability
  • Connections to physics and fault-tolerant quantum computation
  • Notes

    Lecture 6 recording

    Lecture 7: Quantum LDPC codes (II)
  • Properties of hypergraph product codes (number of logical qubits and code distance)
  • Classical expander codes
  • Quantum expander codes via the hypergraph product
  • Notes 1 Notes 2

    A3 (revised), due Mar 08, 7pm on Crowdmark

    Lecture 7 recording

    Lecture 8: What is fault-tolerance and fault-tolerant operations (I)
  • Definition(s) of fault-tolerance
  • Standard "circuit noise" error model
  • Fault-tolerant error correction (Shor and Flag)
  • Fault-tolerant state preparation
  • Fault-tolerant measurements
  • Notes 1 Notes 2

    Lecture 8 recording

    Lecture 9: Fault-tolerant operations (II)

  • Clifford group (recap)
  • Fault-tolerant gates
  • Transversal gates
  • Eastin-Knill theorem
  • 15 qubit Reed-Muller code
  • Logical gates via teleportation
  • Magic state distillation
  • Notes 1 Notes 2

    A4, due Mar 22, 7pm on Crowdmark

    Lecture 10: Threshold theorem

  • Formal fault-tolerance definitions
  • Local stochastic noise
  • Level reduction theorem
  • Concatenated codes
  • Proof of the threshold theorem
  • Assumptions of the threshold theorem
  • Notes 1 Notes 2

    A5, due April 12, 7pm on Crowdmark

    Term project areas (additional applications of QECC):

  • fault-tolerance with the toric code, anyons and topological quantum computation
  • QECC and topological phases, and other applications of QECC to many body physics
  • single-shot error correction
  • flag fault-tolerant quantum error correction and computation
  • applications of QECC to quantum cryptography (nonlocal games, quantum key distillation, self-testing, secret sharing)
  • quantum error correction and entanglement purification
  • the HaPPY code: toy models for the AdS/CFT bulk/boundary correspondence
  • Note: scheduling and content are subject to minor changes