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Related Concept Videos

The Uncertainty Principle04:08

The Uncertainty Principle

Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He mathematically...
Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis. This...
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Stability of Equilibrium Configuration

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Carrier Generation and Recombination

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Atomic Nuclei: Types of Nuclear Relaxation01:28

Atomic Nuclei: Types of Nuclear Relaxation

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NMR Spectrometers: Resolution and Error Correction

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Related Experiment Video

Updated: Jun 25, 2026

Gradient Echo Quantum Memory in Warm Atomic Vapor
10:00

Gradient Echo Quantum Memory in Warm Atomic Vapor

Published on: November 11, 2013

Nonequilibrium reliability of quantum memories.

Alastair Kay1

  • 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany.

Physical Review Letters
|March 5, 2009
PubMed
Summary

The Toric code quantum memory cannot store information for long due to noise. The 2D Ising model, however, protects classical information against similar noise for extended periods.

Area of Science:

  • Quantum information science
  • Topological quantum computation
  • Condensed matter physics

Background:

  • Storing quantum information reliably is crucial for quantum computing.
  • The Toric code is a leading model for quantum error correction.
  • Understanding noise effects on quantum memory is essential.

Purpose of the Study:

  • To investigate the limitations of the 2D Toric code as a quantum memory under realistic noise conditions.
  • To identify conditions for overcoming these limitations.
  • To compare the robustness of the Toric code with other models like the 2D Ising model.

Main Methods:

  • Analyzing the interplay between Hamiltonian perturbations and dynamic noise in a system's ground state.
  • Simulating a 2D Toric code with N^2 qubits in contact with a thermal reservoir.

Related Experiment Videos

Last Updated: Jun 25, 2026

Gradient Echo Quantum Memory in Warm Atomic Vapor
10:00

Gradient Echo Quantum Memory in Warm Atomic Vapor

Published on: November 11, 2013

  • Evaluating information storage time scales.

    • Main Results:

    • The 2D Toric code, when used as a quantum memory, exhibits information decay in time O(N).
    • The 2D Ising model demonstrates exponential protection of classical information against the same noise model.
    • The findings highlight limitations in braiding operations within topological quantum computation.

    Conclusions:

    • The 2D Toric code is not suitable for long-term quantum information storage under the studied noise conditions.
    • The 2D Ising model offers a more robust alternative for classical information protection.
    • Results impact the design of fault-tolerant topological quantum computers.