Relevance: GS-3 (Science & Tech – Quantum Mechanics); Source: The Hindu

A new single-atom experiment has offered fresh clarity on a century-old debate between Albert Einstein and Niels Bohr on the nature of quantum reality.

The Core Quantum Conundrum

Quantum particles show wave–particle duality: they behave like waves until measured, after which they behave like particles.

• Einstein’s view: Quantum mechanics is incomplete; particles must have definite properties even when unobserved.
• Bohr’s view: Measurement defines reality; properties do not exist in a fixed state before observation.

• The Experiment

Scientists used an individual atom to test whether measurement truly determines the state of a quantum system.

• Final Result

The outcome supports Bohr: quantum behaviour collapses only when observed — confirming the standard Copenhagen interpretation.

Significance: Strengthens foundational quantum theory and enhances future technologies such as quantum computing, secure communication, and precision sensors.

Q. Consider the following statements regarding quantum mechanics:

1. Wave–particle duality implies that a particle can exhibit interference only when its path is not measured.
   
2. Einstein supported the idea of intrinsic uncertainty as a fundamental law of nature.
   
3. The Copenhagen interpretation argues that physical properties exist independently of observation.
   

Which of the above statements is/are correct?
(a) 1 only
(b) 1 and 2
(c) 2 and 3
(d) 1, 2 and 3

Answer: (a)