An atom is a billionth of the nano, which is itself a billionth. An Austrian team was able to measure time on the order of attoseconds, while an American team measured a weight of less than one attogram. When there are applications for this, we will pass from the era of nanotechnology to the era of autotechnology
Uriel Brizon, Haaretz
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In recent years there has been a lot of talk about nanotechnology and the advantages inherent in sizes that are a billion times smaller than those we are familiar with on a daily basis. Well, you should get used to a new term: auto-technology. Atto is the billionth part of the nano. If, for example, a nanosecond is a billionth of one second, an attosecond is a billionth of a nanosecond. The slow is therefore the nano of the nano.
Austrian scientists have succeeded for the first time in measuring periods of time on the order of attoseconds. The experiment constitutes an advance in technology, which may be used to build future atomic clocks with much greater accuracy than is currently possible. In the USA, scientists were able to measure a weight smaller than one gram. The measurement was carried out by a device, which could be used in the future to distinguish between different strains of viruses according to their weight.
A nanosecond is such a short period of time that we cannot imagine it. A beam of light moves at a speed of 300 kilometers per second and is capable of circling the Earth more than seven times in one second. For comparison, during a nanosecond the light beam will move only thirty centimeters. In a second, which is a billion times shorter, the light beam will pass through the diameter of only a few atoms per second. To try to understand how small an attogram is, you can think of the following analogy: if one attogram was a cubic meter of water, then one gram would be equal to all the oceans and all the seas on Earth.
A research team from the Vienna University of Technology, led by Dr. Frank Kraus, performed an experiment with the aim of examining the paths of electrons around the atomic nucleus. In the experiment, timed pulses of ultraviolet light were used to cause the scattering of the electrons. An array of sensitive sensors measured the momentum of the electrons, which were scattered under the influence of light. Since momentum is the product of speed and mass, and that the mass of all electrons is equal, it was possible to calculate the different speeds of individual electrons.
The experiment achieved its goal and enabled examination of the electron orbits; But as a byproduct, the experiment also set a new record in the precision of time measurement: the data of the electrons were calculated to an accuracy of one hundred attoseconds. The details of the experiment were published a few weeks ago in an article in the journal "Nature". In an interview on the journal's website, Dr. Kraus stated that his team is now working to perfect the method and try to measure events in time periods of only ten attoseconds. In addition to possible applications in time measurement, the researchers note that the ability to examine the actions of electrons in time periods of attoseconds may lead to a better understanding of the phenomenon of superconductivity (zero resistance to current).
Interestingly, the "eto" limit was broken in a completely different field around the same time. A team of scientists from Cornell University in the USA, led by Dr. Harold Craighead, built a microscopic device that functions as scales. The device makes it possible to measure weights smaller than one gram. The scientists used production methods similar to those used by the computer industry. Using electron beams, a narrow arm was shaped from silicon crystals. Similar to normal scales, the measurement is performed by placing the measured body at the end of the arm. A laser beam measures the change in the movement of the arm and allows calculation of the weight placed at the end. In the tests conducted for the facility, the weight of a gold crumb was measured with great precision - 39 hundredths of an atto-gram (about ten thousand atoms of gold alone). The facility will enable the measurement of the weight of microscopic bodies such as viruses. The ability to measure the weight of such small biological bodies will allow better classification and identification than before. The details of the experiment will appear soon in the "Journal of Applied Physics".
According to quantum mechanics, the physical theory that describes the behavior of tiny particles, it is not possible to accurately measure certain sizes without harming the accuracy of the measurement of other sizes. Such pairs are called "adjoint quantities" (for example, momentum and position, energy and time). This principle is known as the Heisenberg Uncertainty Principle, named after the German scientist who formulated it in 1927. The principle is counterintuitive, but it follows directly from the equations of quantum mechanics, which, unlike classical physics, are not based on absolute quantities but on statistical distributions.
Due to the uncertainty principle, there are special difficulties in measuring very small sizes. Such precise measurements pose a challenge in themselves, but the fact that uncertainties about the contiguous sizes must be taken into account in each experiment piles up additional difficulties. The smaller the measured size, the more complex methods are required to make the measurement. The Austrian group was able to reach the exact results by carefully coordinating the light rays that scattered the electrons and the sensors; The American group reached the desired accuracy by reducing the measuring arm of the device as much as possible and using a laser to measure its fluctuations.
The ability to control small sizes is essential for advanced technology. In computer systems, for example, millions of components are squeezed into a silicon chip thanks to their tiny size. To operate efficiently, computers must perform calculation operations in very short periods of time. For example: a computer with a processor running at a rate of one gigahertz performs an operation every nanosecond. The time required for the processor to retrieve one piece of data from memory is about forty nanoseconds. At this stage, it is not possible to build computers that operate at the speed of attoseconds, but the very fact that such time periods were measured in the laboratory is a significant achievement and perhaps a hint for future technologies.
The studies of the Austrian and American groups are preliminary and it will probably take a long time before useful auto-technology applications are developed. But the ability to handle these sizes has now been proven in practice and the door to future applications is open.
With the publication of the experiment, Dr. Craighead stated that he believes that his team will be able to improve the facility that was developed and soon measure weights as small as a thousandth of an autogram. According to the scientific numbering system, a half-hato is a Zepto, but there is nothing to talk about Zepto-technology, yet.
Physics expert
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