This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Quantum computers promise to tackle problems that are extraordinarily difficult for today's computers. But there is a major obstacle: quantum systems are notoriously fragile.
Noise, loss and even tiny disturbances can destroy the delicate behavior that gives them their power. Building systems with many quantum particles is also extremely challenging. Now, physicists at Louisiana State University have demonstrated a different route.
Instead of starting with a fragile source of quantum light, the team begins with bright, readily available classical light and uses an optical network together with measurements that count photons one by one. This combination reveals and uses hidden multiphoton quantum behavior for information processing. In a study published in Advanced Science, researchers in LSU's Department of Physics & Astronomy report the first robust multiphoton quantum reservoir of its kind to operate at room temperature while tolerating substantial noise and loss.
The platform accesses multiparticle systems with up to 40 photons, simulates complex quantum dynamics, and uses the same optical machine to learn several very different mathematical functions. Bright classical light is much easier to produce than delicate quantum states and can contain large numbers of photons. Yet, from one measurement to the next, the number of photons reaching a detector naturally changes.
The LSU team turned these fluctuations into a resource for quantum information processing. Using photon-number-resolving detectors, which can distinguish how many photons arrive at a time, the researchers selected specific photon-number events. This allowed them to access different multiphoton quantum systems contained within the same classical light field.
The researchers then combined three properties of light: polarization, spatial structure and photon number. Together, these properties created a vast network of possible states and connections that formed a multiphoton quantum reservoir. In the experiment, this reservoir provided 861 measurable components for processing information.
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