Exploiting the void: MIT takes control of quantum randomness for the first time

MIT researchers have successfully controlled quantum randomness using “vacuum fluctuations,” introducing a breakthrough in probabilistic computing with potentially wide-ranging applications.

Groundbreaking research demonstrates the ability to control quantum fluctuations, opening up the potential for probabilistic computing and ultra-precise field sensing.

A team of researchers from the Massachusetts Institute of Technology (WITH) has achieved a major milestone in quantum technology, demonstrating for the first time the ability to control quantum randomness.

The team of researchers focused on a unique feature of quantum physics called “vacuum fluctuations.” You can think of a vacuum as a completely empty space with no matter or light. However, in the quantum world, even this “empty” space undergoes fluctuations or changes. Imagine a calm sea suddenly having waves – it’s similar to what happens in a vacuum at the quantum level. In the past, these fluctuations have allowed scientists to generate random numbers. They are also responsible for many fascinating phenomena that quantum scientists have discovered over the past hundreds of years.

Experimental setup to generate tunable random numbers from vacuum fluctuations. Photo credit: Charles Roques-Carmes, Yannick Salamin

These findings were recently described in the journal Science, in a paper led by MIT postdoctoral associates Charles Roques-Carmes and Yannick Salamin; MIT professors Marin Soljačić and John Joannopoulos; et al.

Computers in a new light

Typically, computers operate in a deterministic manner, executing step-by-step instructions following a predetermined set of rules and algorithms. In this model, if you run the same operation multiple times, you always get identical results. This deterministic approach has powered our digital age, but it also has limitations, especially when simulating the physical world or optimizing complex systems, tasks that Cases often involve a large degree of uncertainty and randomness.

Artistic illustration of tunable random number generation from a quantum vacuum. Credit: Lei Than

This is where the concept of calculating probabilities comes into play. Probabilistic computing systems take advantage of the intrinsic randomness of certain processes to perform computations. They provide not only a single “correct” answer but also a range of possible outcomes with their associated probabilities. This inherently makes them well suited for simulating physical phenomena and solving optimization problems where multiple solutions may exist and exploring different possibilities may lead to a solution. better method.

Dr. Charles Roques-Carmes, one of the main authors of the work, operates the experimental system. Credit: Anthony Tulliani

Overcoming quantum challenges

However, practical implementations of probabilistic computing have historically been hindered by a significant obstacle: the lack of control over the probability distribution associated with quantum randomness. However, research conducted by the MIT team has shed light on a possible solution.

Specifically, the researchers showed that introducing a weak laser “bias” into an optical parametric oscillator, an optical system that naturally generates random numbers, can play a role. acts as a controllable source of “biased” quantum randomness.

“Despite extensive research on these quantum systems, the influence of very weak bias fields remains unexplored,” commented Charles Roques-Carmes, a researcher on the study. “Our discovery of controllable quantum randomness not only allows us to revisit decades-old concepts in quantum optics but also opens up potential in probabilistic computing and sensing. extremely precise field variables.”

The team successfully demonstrated the ability to control the probabilities associated with the output state of an optical parametric oscillator, thereby creating a controllable photonic probability bit (p-bit). first time. In addition, the system shows sensitivity to temporal oscillations of deflection field pulses, which is even much lower than that of single oscillations. photon level.

Dr. Yannick Salamin, one of the main authors of the work, operates the experimental system. Credit: Allyson Mac Basino

Meaning and future prospects

Yannick Salamin, another team member, commented: “Our photonic p-bit generation system currently allows the production of 10,000 bits per second, each of which can follow an arbitrary binomial distribution. We expect that this technology will mature over the next few years, leading to higher speed photonic p-bits and a broader range of applications.”

Professor Marin Soljačić from MIT emphasizes the broader implications of the research: “By making vacuum fluctuations a controllable factor, we are pushing the boundaries of what is possible in quantum enhanced probabilistic computing. The prospects for simulating complex dynamics in areas such as combinatorial optimization and lattice quantum chromodynamics simulation are very exciting.”

Reference: “Quantum vacuum orientation for controlling macroscopic probability distributions” by Charles Roques-Carmes, Yannick Salamin, Jamison Sloan, Seou Choi, Gustavo Velez, Ethan Koskas, Nicholas Rivera, Steven E. Kooi, John D. Joannopoulos and Marin Soljačić, July 13, 2023, Science.
DOI: 10.1126/science.adh4920