Quantum Noise

PWOnlyIAS

July 16, 2025

Quantum Noise

Recently, new research by Raman Research Institute reveals that quantum noise, once seen as a threat to quantum systems, can preserve or even generate intraparticle entanglement, challenging traditional views on decoherence and quantum stability.

About Quantum Noise

Quantum Noise

  • Definition: Quantum noise refers to the inherent, unavoidable fluctuations in physical systems at the quantum level, fundamentally limited by the Heisenberg Uncertainty Principle.
    • Heisenberg Uncertainty Principle: Formulated by the German physicist and Nobel laureate Werner Heisenberg in 1927, the uncertainty principle states that we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy.
  • Sources of Noise: 
    • Intrinsic (Fundamental):
      • Vacuum Fluctuations: Inherent random energy changes even in empty space.
      • Shot Noise: Fluctuations due to the discrete, random arrival of particles.
    • Extrinsic (Environmental & Instrumental):
      • Thermal fluctuations, electromagnetic interference, mechanical vibrations.
      • Imperfections in quantum gates, crosstalk, and instrumentation noise.

Types of Quantum Noise Explored in Research

  • Amplitude Damping: Represents energy loss in the system (e.g., an excited state decaying).
  • Phase Damping: Disrupts critical phase relationships for quantum interference.
  • Depolarizing Noise: Randomly alters the quantum state in all directions, causing a loss of superposition and entanglement.

Intraparticle vs Interparticle Entanglement

  • Intraparticle Entanglement: Occurs within a single particle—for example, between a photon’s spin and polarization.
    • Key Finding: Intraparticle entanglement can survive, revive, or even be generated under certain noise conditions.
  • Interparticle Entanglement: Occurs between two distinct particles.
    • Key Finding: This form of entanglement degrades irreversibly in the presence of the same quantum noise—highlighting the unique resilience of intraparticle systems.

About Quantum Entanglement

  • A quantum phenomenon where two or more particles become interconnected, meaning their individual quantum states cannot be described independently, even when separated. 
  • Measuring a property of one entangled particle instantly influences the other, a concept Einstein called “spooky action at a distance.”
  • Particles become entangled through interaction or conservation laws. Before measurement, entangled particles exist in a shared quantum state (superposition). Upon measurement of one, the state of the other is instantly determined, demonstrating the non-local nature of quantum mechanics.

Basic Example of Entanglement

  • A photon hits a 50-50 beam splitter → enters a superposition of:
    • Photon in path A, none in B
    • Photon in path B, none in A
  • Until measurement, it’s in both states simultaneously.
  • Measuring one path affects the probability of finding the photon in the other, even over large distances.

How Quantum Entanglement Works?

  • A light source emits two photons simultaneously.
  • The polarizations of both photons are entangled — they may be random individually, but always match each other.
    • Polarization: Direction of oscillation of the electric field in a light wave (e.g., vertical, horizontal).

Significance of the Discovery

  • Paradigm Shift: Reframes noise not only as a destructive force but as a potential constructive agent in quantum systems.
  • Decoherence Resistance: Intraparticle entanglement’s ability to withstand and regenerate in noisy environments paves the way for more stable quantum technologies.
  • Quantum System Design: Offers new frameworks for quantum communication, quantum computing, cryptography, and error correction, using noise-resistant architectures.
  • Cross-Platform Validity: The findings are platform-independent, applicable across photons, neutrons, trapped ions, etc., owing to the global noise model used—which considers the particle as a whole rather than isolated components.

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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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