Discovery of quantum entanglement could lead to breakthrough in measuring ultrafast events

In a landmark 1935 paper, Albert Einstein, Boris Podolsky, and Nathan Rosen published what became the world’s first glimpse of one of the truly strange aspects of the quantum world: what physicists now call quantum tangle, a phenomenon that seemed to suggest that there were missing pieces in our larger picture of reality.

The main problem concerned the observation that the quantum state of a particle of a group sharing interactions between them could not be described independently of the state of the others. Perhaps most curious of all, the mysterious entangled nature of these interactions seemed to persist even when the particles were separated over great distances, a phenomenon Einstein dubbed “spooky action at a distance.”

“We are therefore led to conclude”, wrote the physicists at the time, “that the description of reality given by a wave function is not complete”.

Entanglement represents one of the main components of quantum mechanics that is absent from classical mechanics. Although it remains mysterious, studies involving it have sometimes led to unique insights into the nature of the quantum world.

This was the case recently for a team of researchers from Purdue University, who claim to have succeeded in generating a new source of light produced by entangled photos, which could help measure ultrafast events. The method developed by the researchers relied on the generation of entangled photons at wavelengths without a natural source, which are in the extreme ultraviolet parts of the spectrum.

In their article, recently published in Physical Examination Research, the team proposed the generation of quantum entangled photon pairs in the extreme ultraviolet regime at measurements of one attosecond, i.e. 1 × 10−18 of a second.

According to study co-author Dr. Niranjan Shivaram, an assistant professor of physics and astronomy at Purdue’s Quantum Science and Engineering Institute, said the entangled photons studied by the team “are guaranteed to arrive at a given location in a very short period of attoseconds, as long as they travel the same distance.

According to Shivaram, the time-of-arrival correlations observed with the new production of these luminous particles allow them to aid in the measurement of ultrafast events.

“An important application is attosecond metrology,” Shivaram said in a statement, which allows researchers to “push the boundaries of measuring phenomena on the shortest time scale.”

“This source of entangled photons can also be used in quantum imaging and spectroscopy,” adds Shivaram, “where entangled photons have been shown to improve the ability to obtain information, but now at XUV wavelengths and even X-rays.”

The study authors note that understanding electrons and their role in the behavior of atoms is fundamental to understanding the timing of such events. Electrons move on time scales that occur at attoseconds, like photons in their study, and femtoseconds (one quadrillionth of a second). To understand electrons, physicists must be able to assess their motion on such remarkably short timescales.

Ultimately, the research Shivaram’s team at Purdue has undertaken has a wide range of applications, including developing ways to control electrons to create chemical reactions, as well as producing unique new materials and even new innovative nanotechnology.

“The possibilities for discovery are many,” said Shivaram, who added that such research could even play a role in studying zeptosecond phenomena – events on time scales of as little as a thousandth of an attosecond – which are currently impossible to explore because no lasers exist. who are capable of creating pulses of such unfathomable durations.

“Our unique approach of using entangled photons instead of photons in laser pulses could allow us to achieve the zeptosecond regime,” says Shivaram, noting that it will require developments that, perhaps over the course of the next half-decade, could allow such measures to finally become a reality.

The team’s paper, “Attosecond intangled photons from two-photon decay of metastable atos: A source for attosecond experiences and beyond”, by Yimeng Wang, Siddhant Pandey, Chris H. Greene and Niranjan Shivaram, was published in Physical examination research and can be read online.

Micah Hanks is editor and co-founder of The Debrief. Follow his work on and on Twitter: @MicahHanks.

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