Characterizing quantum instruments: from non-demolition measurements to quantum error correction

• URL: http://arxiv.org/abs/2110.06954v1
• Date: Wed, 13 Oct 2021 18:00:13 GMT
• Title: Characterizing quantum instruments: from non-demolition measurements to quantum error correction
• Authors: Roman Stricker, Davide Vodola, Alexander Erhard, Lukas Postler, Michael Meth, Martin Ringbauer, Philipp Schindler, Rainer Blatt, Markus M\"uller and Thomas Monz
• Abstract summary: In quantum information processing quantum operations are often processed alongside measurements which result in classical data. Non-unitary dynamical processes can take place on the system, for which common quantum channel descriptions fail to describe the time evolution. Quantum measurements are correctly treated by means of so-called quantum instruments capturing both classical outputs and post-measurement quantum states.
• Score: 48.43720700248091
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In quantum information processing quantum operations are often processed alongside measurements which result in classical data. Due to the information gain of classical measurement outputs non-unitary dynamical processes can take place on the system, for which common quantum channel descriptions fail to describe the time evolution. Quantum measurements are correctly treated by means of so-called quantum instruments capturing both classical outputs and post-measurement quantum states. Here we present a general recipe to characterize quantum instruments alongside its experimental implementation and analysis. Thereby, the full dynamics of a quantum instrument can be captured, exhibiting details of the quantum dynamics that would be overlooked with common tomography techniques. For illustration, we apply our characterization technique to a quantum instrument used for the detection of qubit loss and leakage, which was recently implemented as a building block in a quantum error correction (QEC) experiment (Nature 585, 207-210 (2020)). Our analysis reveals unexpected and in-depth information about the failure modes of the implementation of the quantum instrument. We then numerically study the implications of these experimental failure modes on QEC performance, when the instrument is employed as a building block in QEC protocols on a logical qubit. Our results highlight the importance of careful characterization and modelling of failure modes in quantum instruments, as compared to simplistic hardware-agnostic phenomenological noise models, which fail to predict the undesired behavior of faulty quantum instruments. The presented methods and results are directly applicable to generic quantum instruments.

Related papers

• The curse of random quantum data [62.24825255497622]
  We quantify the performances of quantum machine learning in the landscape of quantum data. We find that the training efficiency and generalization capabilities in quantum machine learning will be exponentially suppressed with the increase in qubits. Our findings apply to both the quantum kernel method and the large-width limit of quantum neural networks.
  arXiv  Detail & Related papers  (2024-08-19T12:18:07Z)
• Understanding and mitigating noise in molecular quantum linear response for spectroscopic properties on quantum computers [0.0]
  We present a study of quantum linear response theory obtaining spectroscopic properties on simulated fault-tolerant quantum computers. This work introduces novel metrics to analyze and predict the origins of noise in the quantum algorithm. We highlight the significant impact of Pauli saving in reducing measurement costs and noise.
  arXiv  Detail & Related papers  (2024-08-17T23:46:17Z)
• Quantum data learning for quantum simulations in high-energy physics [55.41644538483948]
  We explore the applicability of quantum-data learning to practical problems in high-energy physics. We make use of ansatz based on quantum convolutional neural networks and numerically show that it is capable of recognizing quantum phases of ground states. The observation of non-trivial learning properties demonstrated in these benchmarks will motivate further exploration of the quantum-data learning architecture in high-energy physics.
  arXiv  Detail & Related papers  (2023-06-29T18:00:01Z)
• Measurement-induced entanglement and teleportation on a noisy quantum processor [105.44548669906976]
  We investigate measurement-induced quantum information phases on up to 70 superconducting qubits. We use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
  arXiv  Detail & Related papers  (2023-03-08T18:41:53Z)
• Quantum-Error-Mitigation Circuit Groups for Noisy Quantum Metrology [0.0]
  Quantum technologies work by utilizing properties inherent in quantum systems such as quantum coherence and quantum entanglement. Quantum technologies are fragile against an interaction with an environment (decoherence) and in order to utilize them with high accuracy we need to develop error mitigation techniques.
  arXiv  Detail & Related papers  (2023-03-03T10:01:42Z)
• Non-Markovian noise sources for quantum error mitigation [0.0]
  We present a non-Markovian model of quantum state evolution and a quantum error mitigation cost function tailored for NISQ devices. Our findings reveal that the cost function for quantum error mitigation increases as the coupling strength between the quantum system and its environment intensifies.
  arXiv  Detail & Related papers  (2023-02-10T05:10:27Z)
• Quantum Error Mitigation via Quantum-Noise-Effect Circuit Groups [0.0]
  Near-term quantum computers are fragile against quantum noise effects. Traditional quantum-error-correcting codes are not implemented on such devices. We propose quantum error mitigation (QEM) scheme for quantum computational errors.
  arXiv  Detail & Related papers  (2022-05-27T11:21:35Z)
• Mitigating errors by quantum verification and post-selection [0.0]
  We present a technique for quantum error mitigation based on quantum verification, the so-called accreditation protocol, together with post-selection. We discuss the sample complexity of our procedure and provide rigorous guarantees of errors being mitigated under some realistic assumptions on the noise. Our technique also allows for time dependant behaviours, as we allow for the output states to be different between different runs of the accreditation protocol.
  arXiv  Detail & Related papers  (2021-09-29T10:29:39Z)
• Information Scrambling in Computationally Complex Quantum Circuits [56.22772134614514]
  We experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We show that while operator spreading is captured by an efficient classical model, operator entanglement requires exponentially scaled computational resources to simulate.
  arXiv  Detail & Related papers  (2021-01-21T22:18:49Z)
• Quantum information spreading in a disordered quantum walk [50.591267188664666]
  We design a quantum probing protocol using Quantum Walks to investigate the Quantum Information spreading pattern. We focus on the coherent static and dynamic disorder to investigate anomalous and classical transport. Our results show that a Quantum Walk can be considered as a readout device of information about defects and perturbations occurring in complex networks.
  arXiv  Detail & Related papers  (2020-10-20T20:03:19Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.