Applied Physics Joins Yale Engineering

After sharing a long intellectual and working history at Yale, the Department of Applied Physics and the School of Engineering & Applied Science have officially joined forces. As of July 1, 2020, AP is a member of SEAS, joining the School at a pivotal moment in Yale’s history, as the university carries out a set of large-scale strategic investments in science and engineering.

This is a great move for the School of Engineering & Applied Science, Applied Physics, and the university. AP is a crucial link between physics and engineering. By bringing AP into SEAS, that link becomes even more pronounced, and collaborations will surely be all the more fruitful and better resourced.

– Jeffrey Brock; Dean, Yale School of Engineering & Applied Science

Applied Physics has strengths in multiple areas of interest to SEAS, including materials, quantum information, and optics. APPLIED PHYSICS looks forward to partnering with SEAS departments to work together at the frontiers of engineering and applied science.

– Charles Ahn; Department Chair, Applied Physics


Realizing a Vision

The union brings the university one step closer to fulfilling its strategy for the sciences and engineering. The Report of the University Science Strategy Committee noted that Yale has a “great potential to be the first institution with a comprehensive university-wide research and education program in Quantum Science, Engineering and Materials.” Such a program would advance the frontiers of knowledge, train the next-generation workforce for this field, and serve as a valuable meeting ground for students and faculty.

A New Location for Innovations

The inclusion of Applied Physics into SEAS also comes shortly after the announcement of plans for a new state-of-the-art building intended for quantum science, engineering, and materials research. Plans for the building were a priority outlined in the Science Strategy report as a way to bring together the disciplines of Engineering, Applied Physics, and the sciences.

Continuing and Enhancing Collaborations

In recent years, faculty from SEAS and AP have collaborated on numerous research projects, including one that focuses on finding new materials for the hardware of quantum computing. Selected and funded by the U.S. Department of Energy, the ongoing project seeks to develop the core quantum computing and networking components that would make the uncanny world of quantum physics realistic for computing.

Yale Quantum Engineering Gets a Boost From DOE Grant

Another collaboration could lead to important insights about gene regulation and the genome, as well as cancer and other diseases. The project, led by researchers in Engineering and Applied Physics, is supported by an National Science Foundation program that focuses on interdisciplinary approaches to studying chromatin and epigenetic engineering.

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Other collaborations have emerged out of several interdisciplinary research programs, such as the Center for Research on Interface Structures and Phenomena (CRISP), an interdisciplinary materials research center that was funded by the National Science Foundation; the Yale Quantum Institute (YQI), which facilitates research and teaching of quantum science on campus; and the Yale Institute for Nanoscience and Quantum Engineering (YINQE), which focuses on nanoscale research and applications and brings together researchers in the physical sciences and engineering with those in the fields of the medicine and biology.


The Applied Physics faculty are engaged in a broad range of research programs, including quantum computing, superconducting devices, complex materials and new devices based on them, nonlinear optics, nano and micro-optical devices, as well as theoretical studies of novel materials, phenomena and optical microsystems.

Research at Yale's Department of Applied Physics is focused on three main areas:


Recent Research Highlights in


Physicists can predict the jumps of Schrödinger’s cat (and finally save it)

Yale researchers figured out how to catch and save Schrödinger's famous cat, the symbol of quantum superposition and unpredictability, by anticipating its jumps and acting in real time to save it from proverbial doom. In the process, they overturned years of cornerstone dogma in quantum physics.

The discovery enables researchers to set up an early warning system for imminent jumps of artificial atoms containing quantum information.

Schrödinger’s cat is a well-known paradox used to illustrate the concept of superposition — the ability for two opposite states to exist simultaneously — and unpredictability in quantum physics. The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. The superposition theory of quantum physics suggests that until someone opens the box, the cat is both alive and dead, a superposition of states. Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either dead or alive.

The quantum jump is the discrete (non-continuous) and random change in the state when it is observed.

The experiment, performed in the lab of Michel Devoret, the Frederick W. Beinecke Professor of Applied Physics, peers into the actual workings of a quantum jump for the first time. The results reveal a surprising finding that contradicts Danish physicist Niels Bohr's established view — the jumps are neither abrupt nor as random as previously thought.

Yale researchers create a ‘universal entangler’ for new quantum tech

One of the key concepts in quantum physics is entanglement, in which two or more quantum systems become so inextricably linked that their collective state can’t be determined by observing each element individually. Yale researchers developed a “universal entangler” that can link a variety of encoded particles on demand.

The discovery, led by Robert Schoelkopf, Sterling Professor of Applied Physics and Physics and Director of the Yale Quantum Institute, represents a powerful new mechanism with potential uses in quantum computing, cryptography, and quantum communications.

Quantum calculations are accomplished with delicate bits of data called qubits, which are prone to errors. To implement faithful quantum computation, scientists say, they need “logical” qubits whose errors can be detected and rectified using quantum error correction codes.

“We’ve shown a new way of creating gates between logically-encoded qubits that can eventually be error-corrected,” said Schoelkopf. “It’s a much more sophisticated operation than what has been performed previously.”

$16M grant bolsters Yale’s quantum computing research

Yale’s next wave of quantum computing research will get a boost from a $16 million grant from the U.S. Army Research Office.

The four-year grant will help fund the work of dozens of faculty members, graduate students, and postdoctoral researchers affiliated with the Yale Quantum Institute. The grant also will help pay for a variety of specialized technical gear, including electronics and cooling equipment.

The goal: To construct a “nearly perfect quantum computer out of imperfect parts,” according to the researchers.

“This is further recognition of Yale’s world-leading position in solid-state quantum computing and quantum information science,” said A. Douglas Stone, the Carl A. Morse Professor of Applied Physics and Physics. “The level of funding this program has achieved in the last decade is unprecedented in the physical sciences at Yale. It’s the largest synergistic research effort I’ve seen in my 30 years here.”

Recent Research Highlights in


New shapes of laser beam ‘sneak’ through opaque media

Researchers have found a way to pre-treat a laser beam so that it enters opaque surfaces without dispersing — like a headlight that’s able to cut through heavy fog at full strength.

The discovery from the lab of Hui Cao, the John C. Malone Professor of Applied Physics, Physics, and Electrical Engineering, has potential applications for deep-tissue imaging and optogenetics, in which light is used to probe and manipulate cells in living tissue.

Sound offers new directions in integrated photonics

Yale scientists demonstrated a new method to control the behavior of light on a silicon chip — specifically, its direction — by using sound waves.

For decades, researchers have tried to adapt widely used optical technologies — including lasers, transmitters, and receivers — to microchip-based devices.

“The field of integrated photonics offers potential breakthroughs for applications ranging from energy-efficient communications to precision sensing and quantum information,” explained Peter Rakich, associate professor of applied physics and physics, who led the research team. “It’s very exciting because we’re already seeing these technologies used in practical commercial systems.”

Recent Research Highlights in


‘Picoscience’ and a plethora of new materials

The revolutionary tech discoveries of the next few decades, the ones that will change daily life, may come from new materials so small they make nanomaterials look like lumpy behemoths.

These new materials will be designed and refined at the picometer scale, which is a thousand times smaller than a nanometer and a million times smaller than a micrometer (which itself is smaller than the width of a human hair). In order to do this work, scientists will need training in an array of new equipment that can measure and guide such exquisitely controlled materials. The work involves designing the materials theoretically, fabricating them, and characterizing their properties. At Yale University, they have a name for it; they call it “picoscience.”

A new study moves picoscience in a new direction: taking elements from the periodic table and tinkering with them at the subatomic level to tease out new materials.

Researchers in the lab of Charles Ahn, the John C. Malone Professor of Applied Physics, Mechanical Engineering & Materials Science, and Physics, designed and grew the new material, which is an artificial, layered crystal composed of the elements lanthanum, titanium, cobalt, and oxygen.

The researchers layered the elements one atomic plane at a time, so that one-atom-thick sheets of titanium oxide transfer an electron to one-atom-thick-sheets of cobalt oxide. This changed the electronic configuration and magnetic properties of the cobalt oxide sheet.

They were successful in manipulating the constituent atoms with a precision much smaller than the atom itself. These types of new crystals may form the basis for developing new magnetic materials, where a delicate balance between magnetism and electronic conduction at such small length scales can be manipulated in novel, transistor-like devices that have performance advantages over today’s transistors.

A new topology of matter emerges from artificial spin ice

An intricate lattice of microscopic magnets has led researchers to observe behavior that is reminiscent of the complexities of quantum mechanical systems, but in the context of a purely classical system.

Led by Peter Schiffer, the Frederick W. Beinecke Professor of Applied Physics, researchers discovered new studies of a form of artificial spin ice — a nanometer-scale configuration of magnets so small that their north and south poles spontaneously flip back and forth at room temperature. They found that a particular configuration of artificial spin ice, called Shakti spin ice, also displays the sort of topological order more commonly studied in association with quantum mechanical systems.

Yale scientists make a borophene breakthrough

The thinnest flake, just one atom thick, has provided scientists at Yale and the Brookhaven National Laboratory with new insight into a promising material for the next generation of high-speed electronics and a host of practical applications.

Sheets of boron, or borophene — a close cousin of graphene, a material 200 times stronger than steel that promised to revolutionize electronics — were first theorized in the mid-1990s, but synthesizing the material has defied scientists for almost a decade.

These composite materials, atomically thin with the greatest surface-to-mass ratios, are valuable for solar cells and energy storage, and are also accelerating the development of the fastest and smallest transistors, new touch screens, batteries, and water filters. The challenge has been how to turn these naturally abundant elements into technologically useful materials.

Working with scientists at Yale's Energy Sciences Institute on West Campus, Sohrab Ismail-Beigi, professor of applied physics, physics, and mechanical engineering & materials science, successfully took the next step in modifying the crystal structure of borophene by growing large, device-size crystals up to 100 square micrometers in size on copper surfaces.

The work has set the stage for fabricating borophene-based devices and brings closer the idea of borophene as a model for artificial 2D materials development.