Dom Williamson
@domwilliamson.bsky.social
Topological phases of matter and fault-tolerant quantum computing at The University of Sydney.
Reposted by Dom Williamson
We are offering 4 PhD scholarships in #physics and #astronomy topics @sydney.edu.au
Including:
* FRBs with @manishacaleb.bsky.social
* Quantum critical points with @domwilliamson.bsky.social
* Nanostructured materials with @boriskuhlmey.bsky.social
www.sydney.edu.au/scholarships...
⚛️ 🔭 ☄️ 🧪
Including:
* FRBs with @manishacaleb.bsky.social
* Quantum critical points with @domwilliamson.bsky.social
* Nanostructured materials with @boriskuhlmey.bsky.social
www.sydney.edu.au/scholarships...
⚛️ 🔭 ☄️ 🧪
Physics Foundation Scholarship
A stipend scholarship to support PhD students who are undertaking research within School of Physics, Faculty of Science at the University of Sydney.
www.sydney.edu.au
November 10, 2025 at 6:49 PM
We are offering 4 PhD scholarships in #physics and #astronomy topics @sydney.edu.au
Including:
* FRBs with @manishacaleb.bsky.social
* Quantum critical points with @domwilliamson.bsky.social
* Nanostructured materials with @boriskuhlmey.bsky.social
www.sydney.edu.au/scholarships...
⚛️ 🔭 ☄️ 🧪
Including:
* FRBs with @manishacaleb.bsky.social
* Quantum critical points with @domwilliamson.bsky.social
* Nanostructured materials with @boriskuhlmey.bsky.social
www.sydney.edu.au/scholarships...
⚛️ 🔭 ☄️ 🧪
Reposted by Dom Williamson
Come and join us: we have 2x Postdoctoral Research Associate positions available at SMRI. Mathematicians of all areas are encouraged to apply (pure, applied, statistics). Please share with your network #MathSky
Closing December 3
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Closing December 3
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
SMRI Postdoctoral Research Associate
Two (2) Full time, 3 years fixed term opportunities. Located at the Sydney Mathematical Research Institute (SMRI) Opportunity to contribute to research focused on pure or applied mathematics or statis...
usyd.wd105.myworkdayjobs.com
November 7, 2025 at 12:19 AM
Come and join us: we have 2x Postdoctoral Research Associate positions available at SMRI. Mathematicians of all areas are encouraged to apply (pure, applied, statistics). Please share with your network #MathSky
Closing December 3
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Closing December 3
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Fault-tolerant logical measurement just got a lot faster!
In new work, we show that code surgeries based on hypergraphs, rather than graphs, allow fast and parallel fault-tolerant logical measurements with low qubit overhead (without requiring the code to be single-shot).
arxiv.org/abs/2510.14895
In new work, we show that code surgeries based on hypergraphs, rather than graphs, allow fast and parallel fault-tolerant logical measurements with low qubit overhead (without requiring the code to be single-shot).
arxiv.org/abs/2510.14895
October 17, 2025 at 5:36 AM
Fault-tolerant logical measurement just got a lot faster!
In new work, we show that code surgeries based on hypergraphs, rather than graphs, allow fast and parallel fault-tolerant logical measurements with low qubit overhead (without requiring the code to be single-shot).
arxiv.org/abs/2510.14895
In new work, we show that code surgeries based on hypergraphs, rather than graphs, allow fast and parallel fault-tolerant logical measurements with low qubit overhead (without requiring the code to be single-shot).
arxiv.org/abs/2510.14895
Very happy that I was scheduled to present first today. Talk about a hard act to follow…
October 14, 2025 at 4:27 PM
Very happy that I was scheduled to present first today. Talk about a hard act to follow…
How do you correct this error in a Layer Code?
In new work arxiv.org/abs/2510.09218 we introduce a concatenated matching decoder and show that Layer Codes assisted by this decoder are partially self-correcting quantum memories at finite temperature!
In new work arxiv.org/abs/2510.09218 we introduce a concatenated matching decoder and show that Layer Codes assisted by this decoder are partially self-correcting quantum memories at finite temperature!
October 13, 2025 at 1:46 AM
How do you correct this error in a Layer Code?
In new work arxiv.org/abs/2510.09218 we introduce a concatenated matching decoder and show that Layer Codes assisted by this decoder are partially self-correcting quantum memories at finite temperature!
In new work arxiv.org/abs/2510.09218 we introduce a concatenated matching decoder and show that Layer Codes assisted by this decoder are partially self-correcting quantum memories at finite temperature!
Layer Codes are partially self-correcting: arxiv.org/abs/2510.09218
Layer codes may not be self-correcting in the strict sense but that isn’t the end of the story. Stay tuned!
October 13, 2025 at 1:31 AM
Layer Codes are partially self-correcting: arxiv.org/abs/2510.09218
Floquet codes fit neatly onto the heavy-hex lattice. In new work out today, we show that making full use of all the heavy-hex qubits allows us to fit two floquet codes at once. We also describe transversal gates and low-depth adaptive circuits to switch to the color code.
arxiv.org/abs/2510.05225
arxiv.org/abs/2510.05225
October 8, 2025 at 4:28 AM
Floquet codes fit neatly onto the heavy-hex lattice. In new work out today, we show that making full use of all the heavy-hex qubits allows us to fit two floquet codes at once. We also describe transversal gates and low-depth adaptive circuits to switch to the color code.
arxiv.org/abs/2510.05225
arxiv.org/abs/2510.05225
Reposted by Dom Williamson
📢 Come be my colleague: the School of Computer Science at 🇦🇺 #USyd is hiring!
Multiple tenure-track-equivalent positions across the board (including theory!), but with a specific focus on Cybersecurity and Trustworthy Digital Systems, and ML/AI.
⏰ Dec 1
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Multiple tenure-track-equivalent positions across the board (including theory!), but with a specific focus on Cybersecurity and Trustworthy Digital Systems, and ML/AI.
⏰ Dec 1
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Multiple Continuing (Tenure-Track) Academic Positions, School of Computer Science, Faculty of Engineering, The University of Sydney
Join a thriving Faculty of Engineering at a University ranked amongst the world’s best teaching and research institutions Located in the heart of Sydney’s bustling inner west quarter, close to beaches...
usyd.wd105.myworkdayjobs.com
September 29, 2025 at 11:45 PM
📢 Come be my colleague: the School of Computer Science at 🇦🇺 #USyd is hiring!
Multiple tenure-track-equivalent positions across the board (including theory!), but with a specific focus on Cybersecurity and Trustworthy Digital Systems, and ML/AI.
⏰ Dec 1
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Multiple tenure-track-equivalent positions across the board (including theory!), but with a specific focus on Cybersecurity and Trustworthy Digital Systems, and ML/AI.
⏰ Dec 1
usyd.wd105.myworkdayjobs.com/en-GB/USYD_E...
Reposted by Dom Williamson
Gauging versus dualities: equivalent up to constant depth quantum circuits. arxiv.org/abs/2509.22051
September 29, 2025 at 7:29 AM
Gauging versus dualities: equivalent up to constant depth quantum circuits. arxiv.org/abs/2509.22051
Join us on a journey through the gauging nexus between topological and fracton phases. In this work we show how to pass through a web of dualities between topological, symmetry-protected, and fractonic phases of quantum matter, and back again.
arxiv.org/abs/2509.19440
arxiv.org/abs/2509.19440
September 25, 2025 at 6:37 AM
Join us on a journey through the gauging nexus between topological and fracton phases. In this work we show how to pass through a web of dualities between topological, symmetry-protected, and fractonic phases of quantum matter, and back again.
arxiv.org/abs/2509.19440
arxiv.org/abs/2509.19440
Another fantastic paper by Noédyn Baspin on arxiv today.
Introducing the free energy barrier for quantum codes and using it to destroy our dreams of a self-correcting quantum memory in 3D based on existing codes.
scirate.com/arxiv/2509.1...
Introducing the free energy barrier for quantum codes and using it to destroy our dreams of a self-correcting quantum memory in 3D based on existing codes.
scirate.com/arxiv/2509.1...
The Free Energy Barrier: An Eyring-Polanyi bound for stabilizer Hamiltonians, with applications to quantum error correction
The lack of an energy barrier in stabilizer Hamiltonians is well known to be an indication of short thermalisation times; and serves as a simple criteria to rule out self-correction. Its applicability...
scirate.com
September 23, 2025 at 6:39 AM
Another fantastic paper by Noédyn Baspin on arxiv today.
Introducing the free energy barrier for quantum codes and using it to destroy our dreams of a self-correcting quantum memory in 3D based on existing codes.
scirate.com/arxiv/2509.1...
Introducing the free energy barrier for quantum codes and using it to destroy our dreams of a self-correcting quantum memory in 3D based on existing codes.
scirate.com/arxiv/2509.1...
Sad news. I had a great time working at IBM Almaden last year. The park that surrounds the campus is amazing.
July 6, 2025 at 8:35 AM
Sad news. I had a great time working at IBM Almaden last year. The park that surrounds the campus is amazing.
I had a great time at @simonsinstitute.bsky.social for the Quantum Algorithms, Complexity, and Fault Tolerance Reunion workshop. The recordings are now up: simons.berkeley.edu/workshops/qu...
Videos
simons.berkeley.edu
June 26, 2025 at 5:40 AM
I had a great time at @simonsinstitute.bsky.social for the Quantum Algorithms, Complexity, and Fault Tolerance Reunion workshop. The recordings are now up: simons.berkeley.edu/workshops/qu...
New work out on p-string condensation via gauging higher-form symmetries.
arxiv.org/abs/2505.13604
Often, gauging a higher-form symmetry leads to a gauge theory. Here we look at gauging a higher-form symmetry on a system of topological layers and we instead find unconventional fracton order!
arxiv.org/abs/2505.13604
Often, gauging a higher-form symmetry leads to a gauge theory. Here we look at gauging a higher-form symmetry on a system of topological layers and we instead find unconventional fracton order!
String-Membrane-Nets from Higher-Form Gauging: An Alternate Route to $p$-String Condensation
We present a new perspective on the $p$-string condensation procedure for constructing 3+1D fracton phases by implementing this process via the gauging of higher-form symmetries. Specifically, we show...
arxiv.org
May 21, 2025 at 6:10 AM
New work out on p-string condensation via gauging higher-form symmetries.
arxiv.org/abs/2505.13604
Often, gauging a higher-form symmetry leads to a gauge theory. Here we look at gauging a higher-form symmetry on a system of topological layers and we instead find unconventional fracton order!
arxiv.org/abs/2505.13604
Often, gauging a higher-form symmetry leads to a gauge theory. Here we look at gauging a higher-form symmetry on a system of topological layers and we instead find unconventional fracton order!
Talks from the recent YITP workshop “Logical Gates for Encoded Qubits” are up! Thanks again to the organizers for putting on a fantastic workshop. My talk about fault-tolerant logical measurement: www.youtube.com/watch?v=k0G0...
Dominic Williamson - Low-overhead fault-tolerant quantum computation by gauging logical operators
YouTube video by YITP Quantum Error Correction Workshop
www.youtube.com
May 19, 2025 at 4:32 AM
Talks from the recent YITP workshop “Logical Gates for Encoded Qubits” are up! Thanks again to the organizers for putting on a fantastic workshop. My talk about fault-tolerant logical measurement: www.youtube.com/watch?v=k0G0...
Check out this short piece about our recent work on low-depth quantum circuit implementations of spin-chain dualities:
phys.org/news/2025-04...
phys.org/news/2025-04...
Study shows that duality operators can be realized as unitary linear-depth quantum circuits
In the context of quantum physics, the term "duality" refers to transformations that link apparently distinct physical theories, often unveiling hidden symmetries. Some recent studies have been aimed ...
phys.org
May 5, 2025 at 11:14 AM
Check out this short piece about our recent work on low-depth quantum circuit implementations of spin-chain dualities:
phys.org/news/2025-04...
phys.org/news/2025-04...
Reposted by Dom Williamson
Section 3 of the Extractor paper is a very good overview I find as a non-expert. arxiv.org/abs/2503.10390
Extractors: QLDPC Architectures for Efficient Pauli-Based Computation
In pursuit of large-scale fault-tolerant quantum computation, quantum low-density parity-check (LPDC) codes have been established as promising candidates for low-overhead memory when compared to conventional approaches based on surface codes. Performing fault-tolerant logical computation on QLDPC memory, however, has been a long standing challenge in theory and in practice. In this work, we propose a new primitive, which we call an $\textit{extractor system}$, that can augment any QLDPC memory into a computational block well-suited for Pauli-based computation. In particular, any logical Pauli operator supported on the memory can be fault-tolerantly measured in one logical cycle, consisting of $O(d)$ physical syndrome measurement cycles, without rearranging qubit connectivity. We further propose a fixed-connectivity, LDPC architecture built by connecting many extractor-augmented computational (EAC) blocks with bridge systems. When combined with any user-defined source of high fidelity $|T\rangle$ states, our architecture can implement universal quantum circuits via parallel logical measurements, such that all single-block Clifford gates are compiled away. The size of an extractor on an $n$ qubit code is $\tilde{O}(n)$, where the precise overhead has immense room for practical optimizations.
arxiv.org
April 7, 2025 at 4:09 PM
Section 3 of the Extractor paper is a very good overview I find as a non-expert. arxiv.org/abs/2503.10390
Reposted by Dom Williamson
Apply now for #quantum PhD #scholarships.
Conduct research under experts at Macquarie Uni, UNSW Sydney, @sydney.edu.au + University of Technology Sydney.
Benefit from competitive stipends, networking + exclusive events.
Open to domestic & international students.
More: bit.ly/3zspfC5
#PhD
Conduct research under experts at Macquarie Uni, UNSW Sydney, @sydney.edu.au + University of Technology Sydney.
Benefit from competitive stipends, networking + exclusive events.
Open to domestic & international students.
More: bit.ly/3zspfC5
#PhD
PhD Scholarships » Sydney Quantum Academy
Our PhD Scholarship program offers students funding to work alongside some of the world’s leading quantum researchers and gain industry-ready skills.
bit.ly
April 2, 2025 at 1:35 AM
Apply now for #quantum PhD #scholarships.
Conduct research under experts at Macquarie Uni, UNSW Sydney, @sydney.edu.au + University of Technology Sydney.
Benefit from competitive stipends, networking + exclusive events.
Open to domestic & international students.
More: bit.ly/3zspfC5
#PhD
Conduct research under experts at Macquarie Uni, UNSW Sydney, @sydney.edu.au + University of Technology Sydney.
Benefit from competitive stipends, networking + exclusive events.
Open to domestic & international students.
More: bit.ly/3zspfC5
#PhD
Very cool new result by Nouédyn Baspin out today showing there are no quantum codes with growing distance and local checks in less than two dimensions. Giving a simple answer to a question I have been curious about for a while.
scirate.com/arxiv/2503.1...
scirate.com/arxiv/2503.1...
Stabilizer codes of less than two dimensions have constant distance
The surface code is a two-dimensional stabiliser code with parameters $[[n,1,\Theta(\sqrt{n})]]$. To this day, no stabiliser code with growing distance is know to live in less than two dimensions. In ...
scirate.com
March 25, 2025 at 6:24 AM
Very cool new result by Nouédyn Baspin out today showing there are no quantum codes with growing distance and local checks in less than two dimensions. Giving a simple answer to a question I have been curious about for a while.
scirate.com/arxiv/2503.1...
scirate.com/arxiv/2503.1...
Reposted by Dom Williamson
Logic gates can often be understood in terms of topological phases, so I often felt it was a shortcoming of my work on a 2D CCZ gate that I did not see the analogous physical picture. So I am pleased to share our work arxiv.org/abs/2503.15751 where we show the gate was a non-Abelian phase all along!
Universal fault tolerant quantum computation in 2D without getting tied in knots
We show how to perform scalable fault-tolerant non-Clifford gates in two dimensions by introducing domain walls between the surface code and a non-Abelian topological code whose codespace is stabilized by Clifford operators. We formulate a path integral framework which provides both a macroscopic picture for different logical gates as well as a way to derive the associated microscopic circuits. We also show an equivalence between our approach and prior proposals where a 2D array of qubits reproduces the action of a transversal gate in a 3D stabilizer code over time, thus, establishing a new connection between 3D codes and 2D non-Abelian topological phases. We prove a threshold theorem for our protocols under local stochastic circuit noise using a just-in-time decoder to correct the non-Abelian code.
arxiv.org
March 21, 2025 at 7:36 AM
Logic gates can often be understood in terms of topological phases, so I often felt it was a shortcoming of my work on a 2D CCZ gate that I did not see the analogous physical picture. So I am pleased to share our work arxiv.org/abs/2503.15751 where we show the gate was a non-Abelian phase all along!
Are you a fan of fault-tolerant non-Clifford gates on the 2D surface code?
Have you been wondering what was really going on in the protocols by Bombín and Brown?
We have a new work for you: arxiv.org/abs/2503.15751
Have you been wondering what was really going on in the protocols by Bombín and Brown?
We have a new work for you: arxiv.org/abs/2503.15751
Universal fault tolerant quantum computation in 2D without getting tied in knots
We show how to perform scalable fault-tolerant non-Clifford gates in two dimensions by introducing domain walls between the surface code and a non-Abelian topological code whose codespace is stabilize...
arxiv.org
March 21, 2025 at 4:21 AM
Are you a fan of fault-tolerant non-Clifford gates on the 2D surface code?
Have you been wondering what was really going on in the protocols by Bombín and Brown?
We have a new work for you: arxiv.org/abs/2503.15751
Have you been wondering what was really going on in the protocols by Bombín and Brown?
We have a new work for you: arxiv.org/abs/2503.15751
If your’e at March Meeting on Friday make sure you get to Oscar and Noah’s awesome session on Advances in Quantum Error Correction Theory. Ted Yoder will be presenting our work on gauging logical operators to perform efficient qLDPC code surgery summit.aps.org/events/MAR-W....
Advances in Quantum Error Correction Theory
8:00 am – 11:00 am, Friday March 21, Session MAR-W11, Anaheim Convention Center, 155 (Level 1)
summit.aps.org
March 20, 2025 at 9:39 PM
If your’e at March Meeting on Friday make sure you get to Oscar and Noah’s awesome session on Advances in Quantum Error Correction Theory. Ted Yoder will be presenting our work on gauging logical operators to perform efficient qLDPC code surgery summit.aps.org/events/MAR-W....
QLDPC codes are a promising approach to efficient quantum memory. However, performing computation on such high-density memory is notoriously difficult.
In a new work, we introduce extractors, which can be attached to any code block to augment it into a quantum processor.
arxiv.org/abs/2503.10390
In a new work, we introduce extractors, which can be attached to any code block to augment it into a quantum processor.
arxiv.org/abs/2503.10390
Extractors: QLDPC Architectures for Efficient Pauli-Based Computation
In pursuit of large-scale fault-tolerant quantum computation, quantum low-density parity-check (LPDC) codes have been established as promising candidates for low-overhead memory when compared to conve...
arxiv.org
March 14, 2025 at 6:22 AM
QLDPC codes are a promising approach to efficient quantum memory. However, performing computation on such high-density memory is notoriously difficult.
In a new work, we introduce extractors, which can be attached to any code block to augment it into a quantum processor.
arxiv.org/abs/2503.10390
In a new work, we introduce extractors, which can be attached to any code block to augment it into a quantum processor.
arxiv.org/abs/2503.10390
Code surgery is a way to perform fault-tolerant quantum logic. Last year, there was a flurry of progress on improving general code surgery. In a new work we synthesize a number of approaches, and some new ideas, into an efficient scheme for parallelized code surgery.
arxiv.org/abs/2503.05003
arxiv.org/abs/2503.05003
March 10, 2025 at 3:43 AM
Code surgery is a way to perform fault-tolerant quantum logic. Last year, there was a flurry of progress on improving general code surgery. In a new work we synthesize a number of approaches, and some new ideas, into an efficient scheme for parallelized code surgery.
arxiv.org/abs/2503.05003
arxiv.org/abs/2503.05003