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But despite creating all these breakthrough technologies, physicists and philosophers who study quantum mechanics still haven’t come up with the answers to some big questions raised by the field’s founders. Given recent developments in quantum information science, researchers like me are using quantum information theory to explore new ways of thinking about these unanswered foundational questions. And one direction we’re looking into relates Albert Einstein’s relativity principle to the qubit.

Quantum computers

Quantum information science focuses on building quantum computers based on the quantum “bit” of information, or qubit. The qubit is historically grounded in the discoveries of physicists Max Planck and Einstein. They instigated the development of quantum mechanics in 1900 and 1905, respectively, when they discovered that light exists in discrete, or “quantum,” bundles of energy.

Quantum computers have the potential to revolutionize our understanding of the world around us—and teach us how to manipulate it. The technology could enable the rapid design and development of life-saving drugs, simulate superconducting materials that would revolutionize technology and clean energy, and even offer insight into the underlying structure of space and time. Like the qubits that sit in superposition at the heart of quantum computers, the possibilities seem endless.

“Right now, you will find people who see quantum computing as a panacea,” says Susanne Yelin, a professor of physics in residence at Harvard’s Faculty of Arts and Sciences. “I am not one of them. But quantum computing could help us better understand fundamental physics, such as problems in condensed matter or particle physics. It could also advance quantum chemistry [which uses quantum physics to understand chemical systems]—and with it, better development of drugs and materials.”

At the Harvard Kenneth C. Griffin Graduate School of Arts and Sciences (Harvard Griffin GSAS), PhD physics students Maddie Cain, on whose dissertation committee Yelin sits, and Dolev Bluvstein are working to make the promise of quantum computing a reality. In the laboratory of Professor Mikhail Lukin, Cain and Bluvstein push the boundaries of science, advancing the prospects of transformative applications that could reshape our world.

Dark states are quantum states in which a system does not interact with external fields, such as light (i.e., photons) or electromagnetic fields. These states, which generally occur due to interferences between the pathways through which a system interacts with an external field, are undetectable using spectroscopic techniques.

Integrated photonic circuits operating at room temperature combined with optical nonlinear effects could revolutionize both classical and quantum signal processing. Scientists from the Faculty of Physics at the University of Warsaw, in collaboration with other institutions from Poland as well as Italy, Iceland, and Australia, have demonstrated the creation of perovskite crystals with predefined shapes that can serve in nonlinear photonics as waveguides, couplers, splitters, and modulators.

Just a few years ago, researchers discovered that changing the angle between two layers of graphene, an atom-thick sheet of carbon, also changed the material’s electronic and optical properties. They then learned that a “twist” of 1.1 degrees—dubbed the “magic” angle—could transform this metallic material into an insulator or a superconductor, a finding that ignited excitement about a possible pathway to new quantum technologies.