An Experimental Test of Quantum Nonlinearity

Supported by a grant from the W. M. Keck Foundation, Mahdi Hosseini and Selim Shahriar aim to build and test an ultra-sensitive optomechanical system to determine whether quantum mechanics is linear or non-linear and whether gravity behaves classically or quantum mechanically

The theory of quantum non-linearity (QNL) proposes that an inherent non-linearity in quantum mechanics may be induced for any massive object due to its gravitational self-energy.

The signal predicted by this theory — which depends on the spatial distribution of its wave function, according to the Schrödinger-Newton Equation (SNE) — is extremely small. Thus, current experiments to test the theory have not achieved the requisite sensitivity.

Mahdi Hosseini (L) and Selim ShahriarNorthwestern Engineering’s Mahdi Hosseini and Selim Shahriar were awarded a three-year, $1.3 million grant from the W. M. Keck Foundation to build and test an ultra-sensitive optomechanical system capable of detecting a shift in the system’s resonance frequency caused by QNL and distinguish it from all possible sources of noise, both quantum and classical.

Hosseini is an associate professor of electrical and computer engineering at the McCormick School of Engineering. Shahriar is a professor of electrical and computer engineering at Northwestern Engineering and professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences.

Research collaborators include Andrew Geraci, professor of physics and astronomy at Weinberg, and Yanbei Chen, professor of physics at the California Institute of Technology.

The team’s “quantum tweezer” optomechanical system aims to achieve extreme isolation from the environmental noise.

“Experimental validation of QNL resulting from the SNE would result in a paradigm shift in our understanding of nature,” Hosseini said. “Specifically, it would establish that at some scale gravity does behave classically. It would also confirm what appears to be the presence of interactions between distinct and parallel realities inherent in quantum theory, without violating causality.”

Hosseini explained that a null result would invalidate the SNE, disprove the existence of mutual gravitational energy between parallel realities, and lend credence to the idea that gravity must indeed be treated quantum mechanically.

About the W. M. Keck Foundation

The W. M. Keck Foundation was established in 1954 in Los Angeles by William Myron Keck, founder of The Superior Oil Company. One of the nation’s largest philanthropic organizations, the W. M. Keck Foundation supports outstanding science, engineering and medical research. The Foundation also supports undergraduate education and maintains a program within Southern California to support arts and culture, education, health and community service projects.

McCormick News Article