Diamonds may now turn out to be a patient's best friend as researchers are using them to refine MRI probes.
A Harvard University-based research team, including a physicist from the National Institute of Standards and Technology (NIST), says that its research into the possibilities of developing quantum computers have led to a finding that may have more immediate application in medical science.
The team has found that a candidate "quantum bit" has great sensitivity to magnetic fields, which hints that MRI-like devices that can probe individual drug molecules and living cells may be possible.
The candidate system, formed from a nitrogen atom lodged within a diamond crystal, is promising not only because it can sense atomic-scale variations in magnetism, but also because it functions at room temperature.
Most other such devices used either in quantum computation or for magnetic sensing can operate only after they are cooled to nearly absolute zero, which makes it difficult to place them near live tissue.
However, using the nitrogen as a sensor or switch could sidestep that limitation.
The researchers point out that, when struck by green light, the nitrogen atom's two excitable unpaired electrons glow a brilliant red.
They say that slight variations in this fluorescence may be used to determine the magnetic spin of a single electron in the nitrogen-a quantum property that has a value of either "up" or "down"-and, thus, may represent one or zero in binary computation.
Their recent achievement was to transfer this quantum information repeatedly between the nitrogen electron and the nuclei of adjacent carbon atoms, forming a small circuit capable of logic operations.
Reading a quantum bit's spin information-a fundamental task for a quantum computer-has been a daunting challenge, but the team demonstrated that by transferring the information back and forth between the electron and the nuclei, the information could be amplified, making it much easier to read.
However, Jacob Taylor, NIST theoretical physicist, still says that the findings are "evolutionary, not revolutionary" for the quantum computing field, and that the medical world may reap practical benefits from the discovery long before a working quantum computer is built.
He envisions diamond-tipped sensors performing magnetic resonance tests on individual cells within the body, or on single molecules drug companies want to investigate-a sort of MRI scanner for the microscopic.
"That's commonly thought not to be possible because in both of these cases the magnetic fields are so small. But this technique has very low toxicity and can be done at room temperature. It could potentially look inside a single cell and allow us to visualize what's happening in different spots," he says.