In News:

A collaborative study led by the Raman Research Institute (RRI), Bengaluru, in association with Indian and international institutions, has made a groundbreaking discovery: quantum noise, often seen as a disruptive factor in quantum systems, may facilitate or even revive quantum entanglement under specific conditions.

Key Scientific Concept: Quantum Entanglement

• Quantum Entanglement: A quantum phenomenon where particles remain interconnected such that the state of one particle instantly influences the state of another, regardless of distance.
• Intraparticle Entanglement: A lesser-known form of entanglement occurring between different properties (degrees of freedom) of a single particle, as opposed to interparticle entanglement (between two or more particles).

The Discovery

• Contrary to long-held assumptions, quantum noise, specifically amplitude damping, can:
  • Revive lost intraparticle entanglement
  • Generate entanglement in initially unentangled intraparticle systems
• In contrast, interparticle entanglement under similar noise conditions only decays without revival.

Types of Quantum Noise Studied

1. Amplitude Damping: Simulates energy loss, akin to an excited state relaxing to a ground state.
2. Phase Damping: Disrupts phase relationships, impacting quantum interference.
3. Depolarizing Noise: Randomizes the quantum state in all directions.

• Key Finding: Intraparticle entanglement is more robust and less susceptible to decay across all three noise types.
• Scientific Tools Used

• Derived an analytical formula for concurrence (a measure of entanglement)
• Developed a geometric representation of how entanglement behaves under noise

Institutions Involved

• Raman Research Institute (RRI) – Lead Institute (Autonomous under DST)
• Indian Institute of Science (IISc)
• Indian Institute of Science Education and Research (IISER), Kolkata
• University of Calgary
• Funded by:
  • India-Trento Programme on Advanced Research (ITPAR)
  • National Quantum Mission (NQM), Department of Science and Technology (DST)

Applications and Significance

• Could lead to more stable and efficient quantum systems
• Implications for Quantum Communication and Quantum Computing
• Results are platform-independent (applicable to photons, trapped ions, neutrons)
• Provides a realistic noise model (Global Noise Model) for practical quantum technologies