Fixed the physics of quantum noise in the LIGO lab – what you need to know?

Researchers from the LIGO project demonstrated how the hyperfine tuning of the devices allows them to push the boundaries of the fundamental laws of physics. Laser-interferometric gravitational-wave Observatory (LIGO) detects gravitational waves arising from catastrophic events in the Universe such as mergers of neutron stars and black holes. These spatio-temporal fluctuations allow scientists to observe the gravitational effects in extreme conditions and to explore fundamental questions about the Universe and its history. Recently, scientists have recorded the motion of a massive object — mirror detector — under the influence of quantum effects. But what does this mean?

Thanks to the work of the laboratories LIGO, VIRGO scientists have been able to detect gravitational waves

What is quantum noise?

Recently physicists have managed to measure the shift of the huge mirrors of the LIGO detector, weighing up to forty pounds. Recall that in the international study group LIGO consists of about 40 research institutes, and the analysis of data coming from the detector and other observatories, employs more than 600 scientists. The main objective is the detection of LIGO and the detection of gravitational waves of cosmic origin that were first predicted by albert Einstein in the General theory of relativity (gr) in 1916.

As shown by the results of a study published in the journal Nature, 40 kg LIGO mirror can move in response to tiny quantum effects, called quantum noise. In physics, quantum noise refers to the uncertainty of the physical quantity due to its quantum origin. In General, quantum noise is a fundamental quantum laws: the uncertainty principle of Heisenberg, according to which some physical quantities cannot be absolutely exact values.

The improvement of instruments and appliances LIGO in the future will open many secrets of the Universe

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In simple words, some values cannot be measured, because the physical laws do not permit. In practice, this means that any measuring device is quantum noise, which is so small that it gets lost in the larger noise, and it cannot be eliminated. However, physicists managed to measure the tiny shift coronarographies mirrors of the LIGO detector. To better understand what is happening, imagine that the fixed shift several times smaller than the hydrogen atom. But why this fixed “quantum shiver” important to modern science?

How does LIGO?

As Heisenberg’s uncertainty principle States that with absolute precision to measure a few physical quantities is impossible, uncertainty, nevertheless, it is possible to reduce one of them, while increasing in the other. Did physics in the study – they reduce the quantum noise and checked, do not change the total noise from all sources and, if so, how. For this they used a special instrument with which to measure the contribution of quantum noise to the displacement of the LIGO mirrors.

This is interesting: Five facts that we know if LIGO will detect the merger of neutron stars

Recall that the core of the LIGO detectors are laser interferometers of kilometer scale, which measure the distance between a 40-pound hanging mirrors with the best precision ever achieved. An unprecedented level of sensitivity of the LIGO is achieved through the most modern equipment, necessary to suppress vibration and thermal noise in the detectors. It is on these levels of sensitivity comes into play in quantum mechanics: the researchers used light pressure on the mirrors and the number of photons in the laser beam. The importance here is the position of the mirrors, since only the first two values have an impact on them.

The LIGO project was proposed in 1992 by Kip Thorne, Ronald Drever of Caltech and Rainer Weiss of Massachusetts Institute of technology.

It is important to understand that the laws of quantum mechanics are the basis of modern technologies including computer, smartphone and any appliance. We know that quantum laws are working.

Thus, the researchers were able to prove that the quantum noise LIGO is uncertainty in the light pressure. All of the above means that at the site LIGO physicists were able to look below the so-called standard quantum limit – the limit, when the measurements are used only natural quantum States.

Were used in the experiment non-classical “squeezed light” which reduces the quantum fluctuations of the laser field. Just a few years ago this type of quantum behavior would be too weak to be observed. But new methods of measurement allow to broaden the horizons of physics, and future enhancements and modernization of tools will improve the sensitivity of existing devices. This means that in the future we will be able to create a gravitational wave of technology that will allow more details to penetrate the space-time and discover the dizzying mysteries of the Universe. So we can have a series of exciting scientific discoveries.

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