702 citations · 1.3k across the 29 of their papers we have counts for
30 papers
Low-Overhead Quantum Error Correction with Boundary-Connected Planar Modules
Oscar Higgott, Hasan Sayginel, Francisco J. H. Heras +11
Realizing practical quantum computers requires quantum error correction, but the most widely implemented approach, the planar surface code, demands a substantial physical qubit ove…
The Virtuous Cycle of Quantum-Classical Machine Learning
Nenad Tomašev, Jarrod R. McClean, Johannes Bausch
Artificial intelligence and quantum computing have both seen tremendous progress in recent years, opening up new avenues for accelerating scientific discovery. Classical machine le…
Quantum error correction below the surface code threshold
Rajeev Acharya, Laleh Aghababaie-Beni, Igor Aleiner +246
Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error rate is suppressed…
Quantum Circuit Optimization with AlphaTensor
Francisco J. R. Ruiz, Tuomas Laakkonen, Johannes Bausch +10
A key challenge in realizing fault-tolerant quantum computers is circuit optimization. Focusing on the most expensive gates in fault-tolerant quantum computation (namely, the T gat…
Learning to Decode the Surface Code with a Recurrent, Transformer-Based Neural Network
Johannes Bausch, Andrew W Senior, Francisco J H Heras +15
Quantum error-correction is a prerequisite for reliable quantum computation. Towards this goal, we present a recurrent, transformer-based neural network which learns to decode the…
Phase Estimation of Local Hamiltonians on NISQ Hardware
Laura Clinton, Johannes Bausch, Joel Klassen +1
In this work we investigate a binned version of Quantum Phase Estimation (QPE) set out by [Somma 2019] and known as the Quantum Eigenvalue Estimation Problem (QEEP). Specifically,…
The Complexity of Approximating Critical Points of Quantum Phase Transitions
James D. Watson, Johannes Bausch
Phase diagrams chart material properties with respect to one or more external or internal parameters such as pressure or magnetisation; as such, they play a fundamental role in man…
Scalable Benchmarks for Gate-Based Quantum Computers
Arjan Cornelissen, Johannes Bausch, András Gilyén
In the near-term "NISQ"-era of noisy, intermediate-scale, quantum hardware and beyond, reliably determining the quality of quantum devices becomes increasingly important: users nee…
General conditions for universality of Quantum Hamiltonians
Tamara Kohler, Stephen Piddock, Johannes Bausch +1
Recent work has demonstrated the existence of universal Hamiltonians - simple spin lattice models that can simulate any other quantum many body system to any desired level of accur…
The Complexity of Translationally Invariant Problems beyond Ground State Energies
James D. Watson, Johannes Bausch, Sevag Gharibian
It is known that three fundamental questions regarding local Hamiltonians -- approximating the ground state energy (the Local Hamiltonian problem), simulating local measurements on…
Fast Black-Box Quantum State Preparation
Johannes Bausch
Quantum state preparation is an important ingredient for other higher-level quantum algorithms, such as Hamiltonian simulation, or for loading distributions into a quantum device t…
Recurrent Quantum Neural Networks
Johannes Bausch
Recurrent neural networks are the foundation of many sequence-to-sequence models in machine learning, such as machine translation and speech synthesis. In contrast, applied quantum…
Translationally-Invariant Universal Quantum Hamiltonians in 1D
Tamara Kohler, Stephen Piddock, Johannes Bausch +1
Recent work has characterised rigorously what it means for one quantum system to simulate another, and demonstrated the existence of universal Hamiltonians -- simple spin lattice H…
Mitigating Errors in Local Fermionic Encodings
Johannes Bausch, Toby Cubitt, Charles Derby +1
Quantum simulations of fermionic many-body systems crucially rely on mappings from indistinguishable fermions to distinguishable qubits. The non-local structure of fermionic Fock s…
A Compact Fermion to Qubit Mapping
Charles Derby, Joel Klassen
Mappings between fermions and qubits are valuable constructions in physics. To date only a handful exist. In addition to revealing dualities between fermionic and spin systems, suc…
Hamiltonian Simulation Algorithms for Near-Term Quantum Hardware
Laura Clinton, Johannes Bausch, Toby Cubitt
The quantum circuit model is the de-facto way of designing quantum algorithms. Yet any level of abstraction away from the underlying hardware incurs overhead. In the era of near-te…
Universal Translationally-Invariant Hamiltonians
Stephen Piddock, Johannes Bausch
In this work we extend the notion of universal quantum Hamiltonians to the setting of translationally-invariant systems. We present a construction that allows a two-dimensional spi…
Uncomputability of Phase Diagrams
Johannes Bausch, Toby S. Cubitt, James D. Watson
The phase diagram of a material is of central importance to describe the properties and behaviour of a condensed matter system. We prove that the general task of determining the qu…
Error Thresholds for Arbitrary Pauli Noise
Johannes Bausch, Felix Leditzky
The error threshold of a one-parameter family of quantum channels is defined as the largest noise level such that the quantum capacity of the channel remains positive. This in turn…
A Quantum Search Decoder for Natural Language Processing
Johannes Bausch, Sathyawageeswar Subramanian, Stephen Piddock
Probabilistic language models, e.g. those based on an LSTM, often face the problem of finding a high probability prediction from a sequence of random variables over a set of tokens…
Undecidability of the Spectral Gap in One Dimension
Johannes Bausch, Toby Cubitt, Angelo Lucia +1
The spectral gap problem - determining whether the energy spectrum of a system has an energy gap above ground state, or if there is a continuous range of low-energy excitations - p…
Perturbation Gadgets: Arbitrary Energy Scales from a Single Strong Interaction
Johannes Bausch
In this work we propose a many-body Hamiltonian construction which introduces only a single separate energy scale of order , for a small parameter , and for …
Classifying Data with Local Hamiltonians
Johannes Bausch
The goal of this work is to define a notion of a quantum neural network to classify data, which exploits the low energy spectrum of a local Hamiltonian. As a concrete application,…
Quantum Codes from Neural Networks
Johannes Bausch, Felix Leditzky
We examine the usefulness of applying neural networks as a variational state ansatz for many-body quantum systems in the context of quantum information-processing tasks. In the neu…