Orchestrating the Nanoscale: Exploring Light and Matter for Quantum Science newswise

Byline: Leah Hesla

lights. Case. Conversation.

The pithy trio of words belies the wide range of science explored by Randall Goldsmith, a professor of chemistry at the University of Wisconsin–Madison. There, he directs nature’s smallest constituents to follow his signals on an atomic-scale stage.

On one side are photons – particles of light. On the other are molecules – particles of matter. Goldsmith discovered and orchestrated their interactions, uncovering events that could be the basis for devices that can detect a single diseased cell in human tissue or carry information over hackerproof networks.

“It’s great how the modern QIS toolkit can control, seemingly, the fate of the electronic states of molecules and atoms… which, to me, is really amazing.” -Randall Goldsmith, University of Wisconsin-Madison

While such next-generation technologies are in their early stages, they are expected to have a widespread impact in the coming decades. quantum information scienceor QIS, which harnesses the power of atoms and molecules for practical use.

As part of Q-Next—a U.S. Department of Energy (DOE) national QIS research center led by DOE’s Argonne National Laboratory—Goldsmith is advancing QIS by choreographing light-and-matter interplay.

“All these partners dancing together can really give you a powerful new perspective on what the molecules are doing,” Goldsmith said. “We can potentially build black boxes that can be deployed in biotechnology, in pharma, in environmental sensing. New opportunities arise when you use nanodevices or nanostructures. ,

Goldsmith is building photonic interfaces – minuscule mirrors and lenses – that measure and manipulate light to illuminate and influence molecules in specific ways.

Take the microcavity technology developed by Goldsmith and his team. This photonic interface is a tiny spot that traps light for a few nanoseconds. Trapped light passes through the molecule as it passes through the cavity, revealing detailed information about the shape and motion of the molecule.

Typically, researchers add fluorescing compounds – compounds that emit light – to chemical reactions to track and visualize them. Goldsmith’s microcavity technology enables scientists to obtain a vivid picture of molecular behavior without the traditional use of fluorescent labels, which can distort how molecules function in nature.

“Photonic devices like this give us a new fully stocked sandbox of new knobs to play with,” Goldsmith said. “You have to get different states of all the molecules to fully capture the physics of the system.”

And someone must capture the physics of the system to design molecules as custom qubits – the fundamental units of quantum information.

Molecular qubits are just one class of qubit, the diversity of which could fill a book. Each category has its own advantages. Goldsmith is drawn to the versatility of molecular qubits, which makes for a well-equipped quantum playground.

“The advantage of molecules is that there are a hundred years of experience in learning how to make them,” he said. “With molecules, you can essentially dial in whatever you want because you have control over the items you put in.”

By tuning various photonic characteristics of the molecule, scientists can control the qubit lifetime and the characteristics of the light it emits as a signal. This fine-tunability enables researchers to design the perfect qubit to take the temperature of a living cell or destroy the data through a quantum communication network.

“Say that your photonic interfaces increase the rate at which they couple to each other. “If you want to get a meaningful data transmission rate, you need that photonic interface, so you’re not hostage to the sloth-like behavior of molecules that will be emitted whenever they do the damn thing,” he said. Said. “If you put them in a photonic interface, you can really tell them to do it quickly. And this applies to the variety of different types of materials that are being seen in Q-Next. ,

Goldsmith is one of several collaborators within Q-Next working on molecular qubits. With David Avshalom, director of Q-Next at the University of Chicago, and Danna Friedman at MIT, Goldsmith is developing customizable qubits that can be used in many applications—an increasingly powerful area of ​​exploration at the Quantum Research Center.

Goldsmith’s enthusiasm for molecular exploration began as an undergraduate at Cornell University, when he learned how molecules could form.

“I became more and more excited about what molecules could do and about using light to learn more about what molecules were doing,” he said. “I was reading Pop Science papers about this idea of ​​using molecules as key elements in very small electronics, as transistors, as wires to conduct charge. ”

After graduate work at Northwestern University and a postdoctoral appointment at Stanford University, Goldsmith joined the University of Wisconsin as a faculty member. There he started the “Wacky Project”, as he called it – it was a new research area for him – building photonic devices and deploying them to observe molecules.

“I was going into an area that I really had no experience in, so it was like a high-risk, high-return project,” he said. “Thankfully, I had some adventure and very, very capable, creative, brilliant and tough students who helped us all learn together to get into photonics.”

And tenacity is one, given the challenge of manipulating information on nature’s smallest scales.

“As a community, we have become very dependent on these photonic devices and nano devices. It is not easy to make them. Making them in a way that is scalable or reproducible is not easy,” Goldsmith said. “We burn through a lot of them, so we have to make a whole bunch of them. Developing ways to smooth that process is not glamorous work, but it is important.

And it takes all kinds of time, he says – physicists, chemists, materials scientists, biologists, biologists, engineers, technicians – for QIS to live up to its potential.

“It’s great how the modern QIS toolkit can control, seemingly, the fate of the electronic states of molecules and atoms,” Goldsmith said. “And that, to me, is really amazing.”

This work was supported by the U.S. Office of Science National Quantum Information Science Research Centers as part of the Q-Next Center.

About Q-Next

Q-Next is a US Department of Energy national quantum information science research center led by Argonne National Laboratory. Q-Next brings together world-class researchers from national laboratories, universities, and US technology companies with the goal of developing the science and technology to control and distribute quantum information. Q-Next partners and institutions have established two national foundries for quantum materials and devices, developed networks of sensors and secure communication systems, established simulation and network test beds, and trained the next generation of quantum-ready workforce. Train to ensure American scientific and economic leadership in this fast-moving field. For more information, visit https://q-next.org/.

Argonne National Laboratory Seeks solutions to pressing national problems in science and technology by conducting leading-edge basic and applied research in almost every scientific discipline. Argon is managed by Chicago Argonne, LLC For US Department of Energy Office of Science.

US Department of Energy Office of Science is the largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science,