# Spectral quantum tomography

@article{Helsen2019SpectralQT, title={Spectral quantum tomography}, author={J. Helsen and F. Battistel and B. Terhal}, journal={npj Quantum Information}, year={2019}, volume={5}, pages={1-11} }

We introduce spectral quantum tomography, a simple method to extract the eigenvalues of a noisy few-qubit gate, represented by a trace-preserving superoperator, in a SPAM-resistant fashion, using low resources in terms of gate sequence length. The eigenvalues provide detailed gate information, supplementary to known gate-quality measures such as the gate fidelity, and can be used as a gate diagnostic tool. We apply our method to one- and two-qubit gates on two different superconducting systems… Expand

#### 13 Citations

Spectral Transfer Tensor Method for Non-Markovian Noise Characterization

- Physics
- 2020

With continuing improvements on the quality of fabricated quantum devices, it becomes increasingly crucial to analyze noisy quantum process in greater details such as characterizing the… Expand

Quantum eigenvalue estimation via time series analysis

- Physics, Mathematics
- 2019

We present an efficient method for estimating the eigenvalues of a Hamiltonian $H$ from the expectation values of the evolution operator for various times. For a given quantum state $\rho$, our… Expand

Supercomputer simulations of transmon quantum computers

- Computer Science, Physics
- 2020

A simulator for quantum computers composed of superconducting transmon qubits is developed and a protocol from the theory of quantum error correction and fault tolerance is tested that systematically improves the performance of transmon quantum computers in the presence of characteristic control and measurement errors. Expand

Estimation of correlations and non-separability in quantum channels via unitarity benchmarking

- Physics
- 2021

The ability to transfer coherent quantum information between systems is a fundamental component of quantum technologies and leads to coherent correlations within the global quantum process. However… Expand

Mitigating coherent noise using Pauli conjugation

- Physics, Computer Science
- 2019

This Article devise a way to search for the optimal Pauli conjugation scheme and apply it to Steane code, 9-qubit Shor code and distance-3 surface code under global coherent $$Z$$ Z noise and show improvement in logical fidelity over twirling. Expand

Deterministic one-way logic gates on a cloud quantum computer

- Physics
- 2021

Zhi-Peng Yang, 2 Alakesh Baishya, Huan-Yu Ku, 3, ∗ Yu-Ran Zhang, Anton Frisk Kockum, Yueh-Nan Chen, 3 Fu-Li Li, † Jaw-Shen Tsai, 6 and Franco Nori 7, 8, ‡ Ministry of Education Key Laboratory for… Expand

Perturbative tomography of small errors in quantum gates

- Physics
- 2021

We propose an efficient protocol to fully reconstruct a set of high-fidelity quantum gates. Usually, the efficiency of reconstructing high-fidelity quantum gates is limited by the sampling noise. Our… Expand

A context-aware gate set tomography characterization of superconducting qubits

- Physics
- 2021

The efficiency of Quantum Characterisation, Verification, and Validation (QCVV) protocols highly hinges on the agreement between the assumed noise model and the underlying error mechanisms. As a… Expand

Model-Independent Simulation Complexity of Complex Quantum Dynamics.

- Medicine, Physics
- Physical review letters
- 2021

A model-independent measure of dynamical complexity based on simulation of complex quantum dynamics using stroboscopic Markovian dynamics and probe the complexity of excitonic transport in light harvesting 2 and Fenna-Matthews-Olson complexes using data from two recent nonlinear ultrafast optical spectroscopy experiments. Expand

Sublinear Time Eigenvalue Approximation via Random Sampling

- Computer Science, Mathematics
- ArXiv
- 2021

We study the problem of approximating the eigenspectrum of a symmetric matrix A ∈ Rn×n with bounded entries (i.e., ‖A‖∞ ≤ 1). We present a simple sublinear time algorithm that approximates all… Expand

#### References

SHOWING 1-10 OF 41 REFERENCES

Introduction to Quantum Gate Set Tomography

- Physics, Mathematics
- 2015

Quantum gate set tomography (GST) has emerged as a promising method for the full characterization of quantum logic gates. In contrast to quantum process tomography (QPT), GST self-consistently and… Expand

Quantum leakage detection using a model-independent dimension witness

- Physics
- 2019

Users of quantum computers must be able to confirm they are indeed functioning as intended, even when the devices are remotely accessed. In particular, if the Hilbert space dimension of the… Expand

Efficient measurement of quantum gate error by interleaved randomized benchmarking.

- Computer Science, Physics
- Physical review letters
- 2012

A scalable experimental protocol is described that consists of interleaving random Clifford gates between the gate of interest and provides an estimate as well as theoretical bounds for the average error of the gate under test, so long as the average noise variation over all Clifford gates is small. Expand

High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits.

- Physics, Medicine
- Physical review letters
- 2016

We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for… Expand

A fast, low-leakage, high-fidelity two-qubit gate for a programmable superconducting quantum computer

- Mathematics, Physics
- 2019

A common approach to realize conditional-phase (CZ) gates in transmon qubits relies on flux control of the qubit frequency to make computational states interact with non-computational ones using a… Expand

Quantification and characterization of leakage errors

- Physics
- 2018

We present a general framework for the quantification and characterization of leakage errors that result when a quantum system is encoded in the subspace of a larger system. To do this we introduce… Expand

Quantum phase estimation of multiple eigenvalues for small-scale (noisy) experiments

- Physics, Mathematics
- 2018

Quantum phase estimation is the workhorse behind any quantum algorithm and a promising method for determining ground state energies of strongly correlated quantum systems. Low-cost quantum phase… Expand

Randomized Benchmarking of Quantum Gates

- Computer Science, Physics
- 2007

A key requirement for scalable quantum computing is that elementary quantum gates can be implemented with sufficiently low error. One method for determining the error behavior of a gate… Expand

Demonstration of qubit operations below a rigorous fault tolerance threshold with gate set tomography

- Computer Science, Physics
- Nature communications
- 2017

Gate set tomography is used to completely characterize operations on a trapped-Yb+-ion qubit and it is demonstrated with greater than 95% confidence that they satisfy a rigorous threshold for FTQEC (diamond norm ≤6.7 × 10−4). Expand

Superconducting quantum circuits at the surface code threshold for fault tolerance

- Physics, Medicine
- Nature
- 2014

The results demonstrate that Josephson quantum computing is a high-fidelity technology, with a clear path to scaling up to large-scale, fault-tolerant quantum circuits. Expand