Quantum physicists visualize yin-yang in entangled light experiment – ScienceAlert

Never let it be said that scholars have no eye for the sublime.

By encoding and deciphering a Chinese symbol for duality and harmony in the quantum states of two entangled photons, physicists have recently demonstrated the superior efficiency of a new analytical technique.

Researchers from Sapienza University in Rome and the University of Ottawa in Canada used a method similar to the popular one 3D technology To quickly and reliably measure particle position information.

By improving existing methods for capturing important details about the different states in entangled particles, the team hopes to provide engineers with new computing and imaging tools that form the basis of quantum technologies.

Individual photons, like any particle, are best described as a slowly evolving set of possibilities before measurement gives them fixed, realistic numbers. Polarization, spin, momentum, and even its position are all as unstable as a coin rolling through the air until a metaphorical hand slaps it in one case.

If two photons share a history of some kind — like two coins pulled from the same wallet — slapping one is like stopping the other mid-flight. Because they are intertwined, knowing something about one will give you a measure of the other as if it were put in place too.

The fundamentals of this game of chance form the basis of quantum computers. Many entangled particles called qubits can have one of their states read out in ways that will quickly answer specially designed mathematical questions.

However, why use just one state when particles have so many non-deterministic properties to choose from, which turns simple two-dimensional qubits into “multi-dimensional” ones? qudits?

To build a more complex picture of a particle, physicists can take a series of measures, just as multiple X-rays are used to build a 3D image of an object. Computed tomography.

One of the main problems in adaptation Quantitative tomography To capture the many dimensions of a particle is work required. As the number of states being read increases, the metrics rise exponentially, which costs time and greatly increases the risk of errors.

Two-photon digital holography could change that. Just as conventional holograms allow us to retrieve three-dimensional information from a two-dimensional surface, the way waves interfere with each other can be used to quickly and accurately infer extra dimensions from just a few details carried between a pair of photons.

Physicists are already using the interference of entangled particles to map hidden objects in what is known as ghost imaging. By knowing enough about the position of a single photon sent along one path, it is possible to learn the secrets of its partner’s journey through a second path through the interference of its waves.

By applying the tricks of holography, the researchers were able to read positional information in the interference of two separate light waves, and recover enough information to recreate the yin and yang symbol programmed into the photon generating device.

As simple as the manifestation of yin and yang, this single still image represents a huge leap in measuring many quantum states in a short time.

“This method is significantly faster than previous techniques, requiring only minutes or seconds rather than days.” He says University of Ottawa physicist Alessio Derico.

“Importantly, detection time is not affected by system complexity – a solution to the long-standing scalability challenge in projective tomography.”

This research was published in Nature photonics.