By Monitoring and controlling spin fluctuations, the method may provide a route for enhancing the resolution of magnetic resonance imaging (MRI) on the nanometer-scale, allowing researchers to make 3D images of smaller objects than ever before. The results have been published in the journal «Nature Physics».
Many of the elements that make up the matter around us, such as hydrogen or phosphorus, contain a magnetic nucleus at the center of each atom. This nucleus acts like a tiny magnet with a north and south pole. By applying a large magnetic field, the poles of these nuclei align along the magnetic field, producing a so-called nuclear spin polarization.
When the nuclei are irradiated with electromagnetic impulses (radio waves) at a very specific frequency, they change their direction away from the magnetic field. Because they are magnetic, the nuclei then start turning back. As they do so, they emit the energy they had previously absorbed through the radio waves. With a special antenna these signals can be detected.
This method is called nuclear magnetic resonance (NMR) and can provide very useful information about a sample, such as its chemical composition or structure. The method also forms the basis of magnetic resonance imaging (MRI), which can make 3D images of the density of an object and is often used on patients in hospitals.
However, for very small objects (i.e. smaller than a single cell) containing a small number of nuclei, the natural fluctuations of the nuclear spin polarization actually become larger than the polarization produced by a large magnetic field. These deviations are known as «spin noise». The fact that spin noise is so dominant at small scales is one of the reasons why measuring NMR and MRI in very small objects is so difficult.
Monitoring, controlling and capturing
The team led by Prof. Martino Poggio from the University of Basel in Switzerland has now demonstrated, together with scientists from Eindhoven University of Technology and Delft University of Technology in the Netherlands, a method for creating polarization order from such random fluctuations. By monitoring, controlling, and capturing statistical spin fluctuations, the team produced polarizations that were much larger than what can be created by applying a magnetic field.
This is the first report of the real-time manipulation, control, and capture of fluctuations arising from nuclear spin noise. The results are immediately relevant to recent technical advances that have dramatically reduced the possible detection volumes of NMR measurements. «Improved understanding of these phenomena may lead to new high resolution nano- and atomic-scale imaging techniques», explains Poggio, Argovia Nanotechnology Professor at the Swiss Nanoscience Institute. The Basel method may provide a route for enhancing the sensitivity of nanometer-scale magnetic resonance imaging (MRI) or possibly for the implementation of solid-state quantum computers.
The method’s ability to reduce nuclear spin polarization fluctuations may also be useful to enhance the coherence time of solid-state qubits. Qubits are units of quantum information used in quantum computers. Qubits implemented in the solid-state – especially in structures called quantum dots – are very susceptible to fluctuations in nuclear polarization: even tiny variations in the nuclear polarization destroy a qubit’s coherence. Therefore, the ability to control these fluctuations may extend qubit coherence times and thus help in the on-going development of solid-state quantum computers. Poggio points out that his «approach to capture and store spin fluctuations is generally applicable to any technique capable of detecting and addressing nanometer-scale volumes of nuclear spins in real-time».
The study was supported by the Canton Aargau, the Swiss National Science Foundation (SNF), the Swiss Nanoscience Institute (SNI), and the National Center of Competence in Research for Quantum Science and Technology (QSIT).
P. Peddibhotla, F. Xue, H. I. T. Hauge, S. Assali, E. P. A. M. Bakkers, M. Poggio
Harnessing nuclear spin polarization fluctuations in a semiconductor nanowire
Nature Physics (2013) | doi: 10.1038/nphys2731
Prof. Martino Poggio, University of Basel, Department of Physics, Tel: +41 61 267 37 61, Mob: +41 79 452 81 97, E-Mail: email@example.com
Christoph Dieffenbacher | Source: Universität Basel
Further information: www.unibas.ch
Further Reports about: 3D images > information technology > large magnetic field > magnetic field > magnetic resonance > magnetic resonance imaging > Manipulation > Monitoring > MRI > Nanoscience > Nature Physics > Noise > Nuclear > Physic > quantum computer > quantum dot > radio waves > spin fluctuations
More articles from Physics and Astronomy:
Three-dimensional view helps laser in building new molecules
06.12.2013 | Max-Planck-Institut für Quantenoptik
NASA Goddard Planetary Instruments Score a Hat Trick
06.12.2013 | NASA/Goddard Space Flight Center
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
06.12.2013 | Materials Sciences
06.12.2013 | Life Sciences
06.12.2013 | Life Sciences
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News