Quantum decoherence from complex saddle points

• URL: http://arxiv.org/abs/2408.16627v1
• Date: Thu, 29 Aug 2024 15:35:25 GMT
• Title: Quantum decoherence from complex saddle points
• Authors: Jun Nishimura, Hiromasa Watanabe,
• Abstract summary: Quantum decoherence is the effect that bridges quantum physics to classical physics. We present some first-principle calculations in the Caldeira-Leggett model. We also discuss how to extend our work to general models by Monte Carlo calculations.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Quantum decoherence is the effect that bridges quantum physics to well-understood classical physics. As such, it plays a crucial role in understanding the mysterious nature of quantum physics represented by Schr\"odinger's cat, for example. Quantum decoherence is also a source of quantum noise that has to be well under control in quantum computing and in various experiments based on quantum technologies. Here we point out that quantum decoherence can be captured by $\textit{complex}$ saddle points in the Feynman path integral in much the same way as quantum tunneling can be captured by instantons. In particular, we present some first-principle calculations in the Caldeira-Leggett model, which reproduce the predicted scaling behavior of quantum decoherence with respect to the parameters of the environment such as the temperature and the coupling to the system of interest. We also discuss how to extend our work to general models by Monte Carlo calculations using a recently developed method to overcome the sign problem.

Related papers

• 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)
• Simple Tests of Quantumness Also Certify Qubits [69.96668065491183]
  A test of quantumness is a protocol that allows a classical verifier to certify (only) that a prover is not classical. We show that tests of quantumness that follow a certain template, which captures recent proposals such as (Kalai et al., 2022) can in fact do much more. Namely, the same protocols can be used for certifying a qubit, a building-block that stands at the heart of applications such as certifiable randomness and classical delegation of quantum computation.
  arXiv  Detail & Related papers  (2023-03-02T14:18:17Z)
• Effect of Quantum Statistics on Computational Power of Atomic Quantum Annealers [6.013018381423765]
  We study how the quantum statistics affects the computational power of quantum annealing. We find that the bosonic quantum annealer outperforms the fermionic case. Our theoretical finding could shed light on constructing atomic quantum annealers using Rydberg atoms in optical lattices.
  arXiv  Detail & Related papers  (2022-09-01T03:33:20Z)
• New Directions in Quantum Music: concepts for a quantum keyboard and the sound of the Ising model [0.0]
  We explore ideas for generating sounds and eventually music by using quantum devices in the NISQ era using quantum circuits. In particular, we first consider a concept for a "qeyboard", where the real-time behaviour of expectation values using a time evolving quantum circuit can be associated to sound features like intensity, frequency and tone.
  arXiv  Detail & Related papers  (2022-04-01T12:45:39Z)
• Kernel-Function Based Quantum Algorithms for Finite Temperature Quantum Simulation [5.188498150496968]
  We present a quantum kernel function (QKFE) algorithm for solving thermodynamic properties of quantum many-body systems. As compared to its classical counterpart, namely the kernel method (KPM), QKFE has an exponential advantage in the cost of both time and memory. We demonstrate its efficiency with applications to one and two-dimensional quantum spin models, and a fermionic lattice.
  arXiv  Detail & Related papers  (2022-02-02T18:00:04Z)
• Quantum tomography explains quantum mechanics [0.0]
  A suggestive notion for what constitutes a quantum detector leads to a logically impeccable definition of measurement. The various forms of quantum tomography for quantum states, quantum detectors, quantum processes, and quantum instruments are discussed. The new approach is closer to actual practice than the traditional foundations.
  arXiv  Detail & Related papers  (2021-10-11T14:09:30Z)
• Efficient criteria of quantumness for a large system of qubits [58.720142291102135]
  We discuss the dimensionless combinations of basic parameters of large, partially quantum coherent systems. Based on analytical and numerical calculations, we suggest one such number for a system of qubits undergoing adiabatic evolution.
  arXiv  Detail & Related papers  (2021-08-30T23:50:05Z)
• Imaginary Time Propagation on a Quantum Chip [50.591267188664666]
  Evolution in imaginary time is a prominent technique for finding the ground state of quantum many-body systems. We propose an algorithm to implement imaginary time propagation on a quantum computer.
  arXiv  Detail & Related papers  (2021-02-24T12:48:00Z)
• 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)
• Quantum supremacy in driven quantum many-body systems [0.0]
  We show that quantum supremacy can be obtained in generic periodically-driven quantum many-body systems. Our proposal opens the way for a large class of quantum platforms to demonstrate and benchmark quantum supremacy.
  arXiv  Detail & Related papers  (2020-02-27T07:20:15Z)

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.