Search Results for author: Johannes Bausch

Found 11 papers, 2 papers with code

General conditions for universality of Quantum Hamiltonians

no code implementations28 Jan 2021 Tamara Kohler, Stephen Piddock, Johannes Bausch, Toby Cubitt

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 accuracy.

Quantum Physics

The Complexity of Translationally Invariant Problems beyond Ground State Energies

no code implementations23 Dec 2020 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 the ground space (APX-SIM), and deciding if the low energy space has an energy barrier (GSCON) -- are $\mathsf{QMA}$-hard, $\mathsf{P}^{\mathsf{QMA}[log]}$-hard and $\mathsf{QCMA}$-hard, respectively, meaning they are likely intractable even on a quantum computer.

Quantum Physics Strongly Correlated Electrons Mathematical Physics Mathematical Physics

Recurrent Quantum Neural Networks

1 code implementation NeurIPS 2020 Johannes Bausch

In this work we construct a quantum recurrent neural network (QRNN) with demonstrable performance on non-trivial tasks such as sequence learning and integer digit classification.

Benchmarking BIG-bench Machine Learning +4

Hamiltonian Simulation Algorithms for Near-Term Quantum Hardware

no code implementations15 Mar 2020 Laura Clinton, Johannes Bausch, Toby Cubitt

In this work, we develop quantum algorithms for Hamiltonian simulation "one level below" the circuit model, exploiting the underlying control over qubit interactions available in principle in most quantum hardware implementations.

Quantum Physics

Uncomputability of Phase Diagrams

no code implementations3 Oct 2019 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.

Quantum Physics Other Condensed Matter Mathematical Physics Mathematical Physics 03D35, 68Q17, 81V70, 82B26

Error Thresholds for Arbitrary Pauli Noise

2 code implementations1 Oct 2019 Johannes Bausch, Felix Leditzky

The error thresholds of these tree graph states outperform repetition and cat codes in large regions of the Pauli simplex, and hence form a new code family with desirable error correction properties.

Quantum Physics Information Theory Information Theory 81P45, 94C15, 94B99, 94A17

A Quantum Search Decoder for Natural Language Processing

no code implementations9 Sep 2019 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.

Classifying Data with Local Hamiltonians

no code implementations2 Jul 2018 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.

General Classification

Quantum Codes from Neural Networks

no code implementations22 Jun 2018 Johannes Bausch, Felix Leditzky

These codes outperform all other known codes for these channels, and cannot be found using a direct parametrization of the quantum state.

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