A nitrogen vacancy (small circles) within a diamond crystal is promising as a little ‘for quantum computers, in part due to its high sensitivity to magnetic fields, a sensibility that could also allow the RM-like studies objects as small as individual molecules or living cells. When the green light hits the nitrogen vacancy, which emits red fluorescence, detection of changes in this fluorescence will allow scientists to extract information. Credit: J. Taylor, NIST
Diamond has long been said, is the best friend of a girl. But a research team, including a physicist at the National Institute of Standards and Technology has recently found that the gems could become the best friend of a patient as well.
The team’s work is aimed at long-term development of quantum computers, but has borne fruit that may have a more immediate application in medical science. His conclusion that a candidate “quantum bit” has great sensitivity to magnetic fields suggested that MRI-like devices that can see individual drug molecules and living cells is possible.
The candidate system consisting of a nitrogen atom presented within a diamond crystal, it is promising not only because they can sense changes in magnetism at the atomic scale, but also because it works at room temperature. Most other devices, is used in quantum computing, or magnetic detection must be cooled to almost absolute zero to operate, making it difficult to place next to living tissue. However, the use of nitrogen as a sensor or a switch could circumvent this limitation.
Diamond, which is composed of pure carbon, sometimes has its imperfections minutes into crystal lattice. A common impurity is a “vacancy of nitrogen,” in which two carbon atoms are replaced by a nitrogen atom, leaving room on the carbon atom other vacancies. Nitrogen vacancies are partly responsible for the famous diamond shine, because it is actually fluorescent: when the green light to strike, two excitable the nitrogen atom of unpaired electrons of a bright red glow.
The team can use variations on this fluorescent light to determine the magnetic spin of a single electron in nitrogen. Spin is a quantum property that has a value of “up” or “down”, and therefore could represent one or binary zero in the calculation. The recent achievement of the team was to transfer the quantum information repeatedly between the electron and nitrogen nuclei adjacent carbon atoms, forming a small circuit capable of logical operations. Reading information from a quantum bit turn-a fundamental task of a quantum computer, has been a daunting challenge, but the team showed that by transferring information back and forth between the electrons and nuclei, the information could be extended, making it much easier to read.
However, the NIST theorist Jacob Taylor said the findings are “evolutionary, not revolutionary” for the field of quantum computing and the world of medicine can reap practical benefits from the discovery long before a quantum computer is built . It is anticipated diamond sensors performing MRI tests on individual cells in the body, or single-molecule drugs companies want to investigate, a kind of MRI scanner for the microscope. “That’s common, does not believe possible, because in both cases the magnetic fields are so small,” Taylor says. “But this technique has very low toxicity and can be performed at room temperature. Could be found within a single cell and allows us to visualize what is happening in different places.”
Harvard University-based team also includes scientists from the Joint Quantum Institute (a partnership of NIST and the University of Maryland), the Massachusetts Institute of Technology and Texas A & M University.
More information: L. Jiang, J.S. Hodges, J.R. Maze, P. Maurer, J.M. Taylor, D.G. Cory, P.R. Hemmer, R.L. Walsworth, A. Yacoby, A.S. Zibrov and M.D. Lukin. Repetitive readout of a single electronic spin via quantum logic with nuclear spin ancillae. Science, DOI: 10.1126/science.1176496 , published online Sept. 10, 2009.
Source: National Institute of Standards and Technology (web)