Faces of the Foundation: Jenny Schloss

The green glow coming from the apparatus in front of Jenny Schloss has an obvious source: buried in that tangle of lenses, wires, and magnets is a green laser, focused on the center of the device. But put on the rose-tinted safety glasses that block out that green light, and another color reveals itself: a red gleam glimpsed deep within the fine-tuned optical and magnetic components.

The red light is luminescence coming off a specially-synthesized diamond at the heart of the apparatus, and of Schloss’s research. The diamond is full of atomic-scale imperfections, with quantum properties that can be harnessed to detect magnetic fields with ludicrous sensitivity: they can sense the magnetic field changes as a single neuron fires, a tiny field about 5 million times weaker than a typical fridge magnet. Schloss and the other members of Ronald Walsworth’s lab at Harvard hope to turn this remarkable physics into a new way of sensing the subtle dynamics of our brains and hearts.

“We already have many tools to image electrical activity in the brain, from microelectrode arrays to EEG,” says Schloss. “But the magnetic fields generated by electrical currents in the body are nice because they don’t get distorted by the intervening tissue.” A carefully-tuned magnetic field imager could rapidly and accurately pick up the activities of many neurons at once, allowing researchers or physicians to see how our thoughts are formed and how our hearts beat by reading the electrical currents that pass through our neurons and our cardiac muscle cells.

In Schloss’s diamonds, atom-sized imperfections called “nitrogen-vacancy centers” give off red light when excited by a green laser. But when the diamonds are bathed in specific wavelengths of microwave radiation, a small change in the the magnetic field can cause a detectable change in how bright each imperfection glows. So by reading the intensity of the red light coming off different parts of the diamond, Schloss can sense the tiny magnetic impulses as individual neurons fire next to the diamond.

Schloss didn’t originally enter her Hertz Fellowship with the aim of studying neurons. A native New Englander, she majored in physics at Oberlin College before starting her Hertz Fellowship at MIT to study the same. For three years at MIT, she worked in the lab of Martin Zwierlein, working to produce exotic states of matter at temperatures a few millionths of a degree above absolute zero. Such research is important for understanding superconductors and so-called “topological insulators.” But, Schloss said, “I wanted to tackle something with a more tangible impact on health and medicine.”

Thanks to the research freedom provided by her Hertz Fellowship, Schloss was able to move to the Walsworth lab at Harvard, where the atoms and molecules she works with are at room temperature, but still have surprising physical properties that could make them useful biological sensors. “I still get to think about the atomic physics every day” says Schloss, “but I also like knowing that these tricks I play with lasers and diamond crystals have meaningful biological applications.”