Enhanced Yellow Fluorescent Protein EYFP as a Protein Qubit
Qubit protein
Qubits in Proteins: Biology and Computing Revolution
A qubit made of enhanced yellow fluorescent protein (EYFP) was discovered by University of Chicago researchers. This Nature finding shows that EYFP works in pure materials and, more critically, living bacterial and mammalian cells. Genetically encoded quantum platforms for nanoscale biological sensing and quantum imaging are possible.
Using Nature's Qubits
Quantum technologies use qubits, which store state superpositions instead of bits. This paper introduces the novel usage of proteins, which are often utilised as fluorescent indicators in biology, as functional qubits. Most qubit platforms use solid-state components like diamond defects or superconducting circuits.
The UChicago researchers found that EYFP has a metastable "triplet state," which allows them to manipulate the electron's magnetic spin like a qubit. They used microwaves and light to initialise, regulate, and read the protein qubit. Laser pulses enabled 20% spin contrast triggered readout at cryogenic temperatures. By using microwave beams, coherent manipulation was achievable, and spin coherence times under dynamical decoupling were comparable to other molecular qubit systems at 16 microseconds.
“It wanted to explore the idea of using a biological system itself and developing it into a qubit, rather than taking a conventional quantum sensor and trying to camouflage it to enter a biological system,” said project co-principal investigator David Awschalom, Liew Family Professor of Molecular Engineering at UChicago PME “The new direction here is harnessing nature to create powerful families of quantum sensors,” he said.
Living System Quantum Robustness
Importantly, the protein qubit revealed that qubits can function in warm, chaotic environments by working well inside live cells. The qubit detected optically produced magnetic resonance signals in E. coli at normal temperature and human kidney cells at low temperature, proving its durability. This finding, which combines quantum information technology with life sciences, opens the door to genetically incorporating quantum sensors into living organisms like fluorescent proteins are used for biological imaging.
Vast Biosensing and Beyond Potential
If validated and expanded, these findings will impact science and medicine. Protein qubits may enable:
Nanoscale sensing: Little magnetic, electric, and temperature changes are detected.
Diagnostics: Outstanding accuracy in tracking complex biochemical events, protein conformations, and drug-target interactions.
Quantum material design: A new platform for molecular-scale qubits that are biologically related.
Peter Maurer, co-principal investigator and assistant professor of molecular engineering at UChicago PME, said its results enable quantum sensing in living systems and a new way to building quantum materials. “In particular, it can now begin to overcome some of the obstacles faced by current spin-based quantum technology by utilising nature’s own tools of evolution and self-assembly.”
Ingenious Experimental Method
EYFP spin states were examined using a custom confocal microscope built by the team. A “clever light trick” employing a weak infrared laser made the protein release stored energy in a controlled flash and send spin information. Microwaves reversed protein spins, creating quantum patterns. Genetic engineering produced EYFP in cells, and observed spin signals matched those of isolated proteins, proving quantum behaviour in cells. This complex structure was created by the children's perseverance and curiosity.
Limitations and Prospects
Although improved, the platform falls behind well-known solid-state sensors as diamond nitrogen-vacancy centres. Low coherence times and sensitivity (millitesla at ambient, microtesla at cryogenic). Photobleaching of fluorescent proteins still limits stability. Increasing coherence, photostability, and spin readout efficiency is critical.
Researchers found several progress avenues:
Deuterium can boost coherence times by substituting nearby hydrogen atoms.
Advanced optical reading devices can boost signal collecting.
Bioengineering for Performance: Controlled development of fluorescent protein spin and optical properties optimises quantum performance.
If sensitivities improve, protein qubits may allow direct electron or nuclear magnetic resonance examinations inside cells, yielding molecular-level insights into biological processes. They could provide new contrast “colors” for multiplexed quantum imaging.
Biology and Quantum Physics Blend
This remarkable research shows how molecular biology and quantum science are merging. Genetically encodable qubits could provide hybrid technologies that use quantum physics to understand life's complicated mechanisms. Nature must cooperate collaboratively for quantum biology's future. Peter Maurer said, “only at a place like UChicago PME was an interdisciplinary approach possible for a project like this that is at the intersection of quantum engineering and molecular biology.” Co-first author Benjamin Soloway remarked, “It is entering an era where the boundary between quantum physics and biology begins to dissolve.” The groundbreaking science will happen there.