IBM's Quantum computer links two quantum revolutions
Using the IBM Q computer, physicists at EPFL have verified for the first time the tight relationship between quantum entanglement and wave-particle duality, showing that the former controls the latter in a quantum system.EPFL already has a longstanding relationship with IBM’s famed quantum computer, with two teams of students placing second in the annual “IBM Q competition” in 2018 and 2020.
The work is published in Physical Reviews A. “We were able to indirectly confirm that the duality of each quantum bit can be turned off completely, or set to any desired amount by controlling the degree of entanglement of the pair,” says Dupertuis.
Quantum revolution #1: Wave-particle duality
Wave-particle duality is the idea that every particle or quantum entity may be described as either a particle or a wave, with the most famous examples being photons (light particles) and electrons. The concept has been debated since the early ages of quantum mechanics, and catalyzed the first quantum revolution at the start of the 20th century, driven by a historic debate between legendary physicists Albert Einstein and Niels Bohr.
Quantum revolution #2: Quantum entanglement
But then, a second quantum revolution began in the 1930s, when Einstein and Erwin Schrödinger discovered an even more bizarre phenomenon: quantum entanglement, which occurs when two or more particles share a single composite quantum state even when they are separated over cosmic distances.
Entanglement really took over scientific and lay imagination when John Bell and Alain Aspect proved theoretically and experimentally, in the 1960s and 1980s respectively, that it was really linked to a fundamental non-locality in physics which Einstein described as “spooky action at a distance”. Today, just like wave-particle duality, entanglement sparked next-generation technological applications, especially parallel manipulation of quantum objects, which is central for quantum computing.