Hafezi Research Group

For the second year in a row, JQI Fellow Mohammad Hafezi has been named a finalist of the Blavatnik National Awards for Young Scientists by the Blavatnik Family Foundation and the New York Academy of Sciences.He is among 31 of the nation’s rising stars in science who will compete for three Blavatnik National Laureate Awards in the categories of Chemistry, Physical Sciences & Engineering, and Life Sciences, and is one of 11 finalists in Physical Sciences & Engineering. Each of the three 2020 National Laureates will win $250,000—the world’s largest unrestricted prize for early-career scientists.

Topological materials have captured the interest of many scientists and may provide the basis for a new era in materials development. On April 10, 2020 in the journal Science Advances, physicists working with Andreas Elben, Jinlong Yu, Peter Zoller and Benoit Vermersch, including JQI Fellow Mohammad Hafezi and former JQI postdoctoral researcher Guanyu Zhu (currently a research staff member at IBM T. J. Watson Research Center), presented a new method for identifying and characterizing topological invariants on various experimental platforms, testing their protocol in a quantum simulator made of neutral atoms.

From 2017, Google has been giving the award called the Google Noisy Intermediate-Scale Quantum (NISQ) award for the academic researchers who collaborated with Google's quantum computing development teams.

Randomness governs many things, from the growth of cell colonies and the agglomeration of polymers to the shapes of tendrils that form when you pour cream into a cup of coffee.Since as early as 1905, scientists have described these seemingly unrelated phenomena in a unified way: as random walks. By imagining that individual particles or molecules are constantly taking steps in a random direction, researchers have successfully modeled many of the complexities of classical physics.More recently, scientists have brought the idea of a random walk to the quantum world, where the “walkers” can exhibit nonclassical behaviors like quantum superposition and entanglement. These quantum random walks can simulate quantum systems and may eventually be used to implement speedy quantum computing algorithms. However, this will require the walker to move in multiple dimensions (2D and higher), which has been difficult to achieve in a manner that is both practical and scalable.Quantum walks that use photons—the quantum particles of light—are particularly promising, since photons can travel long distances as energy in wave form. However, photons don’t carry an electric charge, which makes it difficult to fully control their motion. In particular, photons won’t respond to magnetic fields—an important tool for manipulating other particles like atoms or electrons. To address these shortcomings, researchers at the Joint Quantum Institute (JQI) have adopted a scalable method for orchestrating 2D quantum random walks of photons—results that were recently published in the journal Physical Review Letters. The research team, led by JQI Fellows Edo Waks and Mohammad Hafezi, developed synthetic magnetic fields in this platform that interact with photons and affect the movement of photonic quantum walkers.

The smallest pieces of nature—individual particles like electrons, for instance—are pretty much interchangeable. An electron is an electron is an electron, regardless of whether it’s stuck in a lab on Earth, bound to an atom in some chalky moon dust or shot out of an extragalactic black hole in a superheated jet. In practice, though, differences in energy, motion or location can make it easy to tell two electrons apart.One way to test for the similarity of particles like electrons is to bring them together at the same time and place and look for interference—a quantum effect that arises when particles (which can also behave like waves) meet. This interference is important for everything from fundamental tests of quantum physics to the speedy calculations of quantum computers, but creating it requires exquisite control over particles that are indistinguishable.With an eye toward easing these requirements, researchers at the Joint Quantum Institute (JQI) and the Joint Center for Quantum Information and Computer Science (QuICS) have stretched out multiple photons—the quantum particles of light—and turned three distinct pulses into overlapping quantum waves. The work, which was published recently in the journal Physical Review Letters, restores the interference between photons and may eventually enable a demonstration of a particular kind of quantum supremacy—a clear speed advantage for computers that run on the rules of quantum physics.

Dissipation induces decoherence in a quantum system which is usually detrimental for quantum state engineering and quantum information processing. However, by engineering dissipation properly, it can actually be a useful resource for preparing exotic quantum strongly-correlated states. Now, in a recent published article in PRL, we show that by placing uncorrelated photons in an engineered dissipative environment, the photons pair up and form photon-pair bound states.

Topological protection allows realization of integrated photonic devices that are robust against certain fabrication-induced disorder. However, it is usually challenging to achieve device reconfigurability along with topological robustness. We recently proposed the design of reconfigurable topological photonic device using anomalous Hall effect.

The topological phases of matter are characterized using the Berry phase, a geometrical phase associated with the energy-momentum band structure. The quantization of the Berry phase and the associated wavefunction polarization manifest as remarkably robust physical observables, such as quantized Hall conductivity and disorder-insensitive photonic transport. Recently, a novel class of topological phases, called higher-order topological phases, were proposed by generalizing the fundamental relationship between the Berry phase and quantized polarization, from dipole to multipole moments.

Researchers at the Joint Quantum Institute (JQI) have created the first silicon chip that can reliably constrain light to its four corners. The effect, which arises from interfering optical pathways, isn't altered by small defects during fabrication and could eventually enable the creation of robust sources of quantum light. That robustness is due to topological physics, which describes the properties of materials that are insensitive to small changes in geometry. The cornering of light, which was reported June 17 in Nature Photonics, is a realization of a new topological effect, first predicted in 2017.

JQI Fellow Mohammad Hafezi has been named a finalist for the 2019 Blavatnik National Awards for Young Scientists.He is one of 31 researchers competing for three Blavatnik National Laureate Awards in the categories of Physical Sciences and Engineering, Chemistry and Life Sciences, and is one of 10 finalists in Physical Sciences and Engineering. Each of the three National Laureates will win $250,000—the world’s largest unrestricted prize for early-career scientists. The awards are sponsored by the Blavatnik Family Foundation and the New York Academy of Sciences.