Jonas Helsen
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View article: Clifford testing: algorithms and lower bounds
Clifford testing: algorithms and lower bounds Open
We consider the problem of Clifford testing, which asks whether a black-box $n$-qubit unitary is a Clifford unitary or at least $\varepsilon$-far from every Clifford unitary. We give the first 4-query Clifford tester, which decides this pr…
View article: Quantum PCPs: on Adaptivity, Multiple Provers and Reductions to Local Hamiltonians
Quantum PCPs: on Adaptivity, Multiple Provers and Reductions to Local Hamiltonians Open
We define a general formulation of quantum PCPs, which captures adaptivity and multiple unentangled provers, and give a detailed construction of the quantum reduction to a local Hamiltonian with a constant promise gap. The reduction turns …
View article: Minimizing the number of edges in LC-equivalent graph states
Minimizing the number of edges in LC-equivalent graph states Open
Graph states are a powerful class of entangled states with numerous applications in quantum communication and quantum computation. Local Clifford (LC) operations that map one graph state to another can alter the structure of the correspond…
View article: Trotter error and gate complexity of the SYK and sparse SYK models
Trotter error and gate complexity of the SYK and sparse SYK models Open
The Sachdev-Ye-Kitaev (SYK) model is a prominent model of strongly interacting fermions that serves as a toy model of quantum gravity and black hole physics. In this work, we study the Trotter error and gate complexity of the quantum simul…
View article: Random regular graph states are complex at almost any depth
Random regular graph states are complex at almost any depth Open
Graph states are fundamental objects in the theory of quantum information due to their simple classical description and rich entanglement structure. They are also intimately related to IQP circuits, which have applications in quantum pseud…
View article: Mutual information fluctuations and non-stabilizerness in random circuits
Mutual information fluctuations and non-stabilizerness in random circuits Open
The emergence of quantum technologies has brought much attention to the characterization of quantum resources as well as the classical simulatability of quantum processes. Quantum resources, as quantified by non-stabilizerness, have in one…
View article: Fermionic Hamiltonians without trivial low-energy states
Fermionic Hamiltonians without trivial low-energy states Open
One of the main problems in computational physics is predicting the low-energy behavior of many-body quantum systems. The computational complexity of this problem, however, is relatively poorly understood. A recent major progress in this d…
View article: Noise-mitigated randomized measurements and self-calibrating shadow estimation
Noise-mitigated randomized measurements and self-calibrating shadow estimation Open
Randomized measurements are increasingly appreciated as powerful tools to estimate properties of quantum systems, e.g., in the characterization of hybrid classical-quantum computation. On many platforms they constitute natively accessible …
View article: Quantum PCPs: on Adaptivity, Multiple Provers and Reductions to Local Hamiltonians
Quantum PCPs: on Adaptivity, Multiple Provers and Reductions to Local Hamiltonians Open
We define a general formulation of quantum PCPs, which captures adaptivity and multiple unentangled provers, and give a detailed construction of the quantum reduction to a local Hamiltonian with a constant promise gap. The reduction turns …
View article: Shadow estimation of gate-set properties from random sequences
Shadow estimation of gate-set properties from random sequences Open
View article: Optimizing sparse fermionic Hamiltonians
Optimizing sparse fermionic Hamiltonians Open
We consider the problem of approximating the ground state energy of a fermionic Hamiltonian using a Gaussian state. In sharp contrast to the dense case [1, 2], we prove that strictly -local fermionic Hamiltonians have a constant Gaussian …
View article: Fermionic Hamiltonians without trivial low-energy states
Fermionic Hamiltonians without trivial low-energy states Open
We construct local fermionic Hamiltonians with no low-energy trivial states (NLTS), providing a fermionic counterpart to the NLTS theorem. Distinctly from the qubit case, we define trivial states via finite-depth $\textit{fermionic}$ quant…
View article: Simultaneous single-qubit driving of semiconductor spin qubits at the fault-tolerant threshold
Simultaneous single-qubit driving of semiconductor spin qubits at the fault-tolerant threshold Open
Practical Quantum computing hinges on the ability to control large numbers of qubits with high fidelity. Quantum dots define a promising platform due to their compatibility with semiconductor manufacturing. Moreover, high-fidelity operatio…
View article: A benchmarking procedure for quantum networks
A benchmarking procedure for quantum networks Open
View article: Shadow estimation of gate-set properties from random sequences
Shadow estimation of gate-set properties from random sequences Open
With quantum computing devices increasing in scale and complexity, there is a growing need for tools that obtain precise diagnostic information about quantum operations. However, current quantum devices are only capable of short unstructur…
View article: Thrifty shadow estimation: re-using quantum circuits and bounding tails
Thrifty shadow estimation: re-using quantum circuits and bounding tails Open
Shadow estimation is a recent protocol that allows estimating exponentially many expectation values of a quantum state from ``classical shadows'', obtained by applying random quantum circuits and computational basis measurements. In this p…
View article: Optimizing sparse fermionic Hamiltonians
Optimizing sparse fermionic Hamiltonians Open
We consider the problem of approximating the ground state energy of a fermionic Hamiltonian using a Gaussian state. In sharp contrast to the dense case, we prove that strictly $q$-local $\rm {\textit {sparse}}$ fermionic Hamiltonians have …
View article: Spectral estimation for Hamiltonians: a comparison between classical imaginary-time evolution and quantum real-time evolution
Spectral estimation for Hamiltonians: a comparison between classical imaginary-time evolution and quantum real-time evolution Open
We consider the task of spectral estimation of local quantum Hamiltonians. The spectral estimation is performed by estimating the oscillation frequencies or decay rates of signals representing the time evolution of states. We present a cla…
View article: General Framework for Randomized Benchmarking
General Framework for Randomized Benchmarking Open
Randomized benchmarking refers to a collection of protocols that in the past decade have become central methods for characterizing quantum gates. These protocols aim at efficiently estimating the quality of a set of quantum gates in a way …
View article: Spectral estimation for Hamiltonians: a comparison between classical imaginary-time evolution and quantum real-time evolution
Spectral estimation for Hamiltonians: a comparison between classical imaginary-time evolution and quantum real-time evolution Open
We present a classical Monte Carlo (MC) scheme which efficiently estimates an imaginary-time, decaying signal for stoquastic (i.e. sign-problem-free) local Hamiltonians. The decay rates in this signal correspond to Hamiltonian eigenvalues …
View article: Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates
Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates Open
We propose a method to reliably and efficiently extract the fidelity of many-qubit quantum circuits composed of continuously parametrized two-qubit gates called matchgates. This method, which we call , relies on advanced techniques from ra…
View article: Data & code supplementary to the paper "Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates"
Data & code supplementary to the paper "Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates" Open
Code that executes and interprets the experiment displayed in fig 1 of the manuscript, as well as pickle files containing the actual data collected during the experimental run.
View article: Data & code supplementary to the paper "Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates"
Data & code supplementary to the paper "Matchgate benchmarking: Scalable benchmarking of a continuous family of many-qubit gates" Open
Code that executes and interprets the experiment displayed in fig 1 of the manuscript, as well as pickle files containing the actual data collected during the experimental run.
View article: The complexity of the vertex-minor problem
The complexity of the vertex-minor problem Open
A graph H is a vertex-minor of a graph G if it can be reached from G by the successive application of local complementations and vertex deletions. Vertex-minors have been the subject of intense study in graph theory over the last decades a…
View article: General Framework for Randomized Benchmarking
General Framework for Randomized Benchmarking Open
Randomized benchmarking refers to a collection of protocols that in the past decade have become central methods for characterizing quantum gates. These protocols aim at efficiently estimating the quality of a set of quantum gates in a way …
View article: The complexity of the vertex-minor problem
The complexity of the vertex-minor problem Open
View article: Estimating gate-set properties from random sequences
Estimating gate-set properties from random sequences Open
With quantum computing devices increasing in scale and complexity, there is a growing need for tools that obtain precise diagnostic information about quantum operations. However, current quantum devices are only capable of short unstructur…
View article: A benchmarking procedure for quantum networks
A benchmarking procedure for quantum networks Open
We propose network benchmarking: a procedure to efficiently benchmark the quality of a quantum network link connecting quantum processors in a quantum network. This procedure is based on the standard randomized benchmarking protocol and pr…
View article: Code & data supplementary to "A benchmarking procedure for quantum networks"
Code & data supplementary to "A benchmarking procedure for quantum networks" Open
Scripts for the netsquid simulations that produces figures 2a and 2b in the paper "A benchmarking procedure for quantum networks", together with pickled outputs of these simulations that produce the plots.\n\n \n\nNote that the plotting sc…
View article: Code & data supplementary to "A benchmarking procedure for quantum networks"
Code & data supplementary to "A benchmarking procedure for quantum networks" Open
Scripts for the netsquid simulations that produces figures 2a and 2b in the paper "A benchmarking procedure for quantum networks", together with pickled outputs of these simulations that produce the plots. Note that the plotting scripts (2…