New memory effect is able to change the signature of the Doppler wave

New memory effect changes the signature of the Doppler wave

The scientists discovered a new memory effect. It has the ability to change the signature of the Doppler wave. That unique effect is revealed between relativistic and classical wave modes. In everyday life, the waves are constantly scattered. They are in the conversations that go in the rooms, in the noise of the ocean waves crashing against the shore, in the sound effects bouncing off planes flying by.

These phenomena are capable of manifesting themselves in both gravity and quantum mechanics. Pavel Ginzburg, who is a professor at the School of Electrical Engineering at Tel Aviv University, believes that they are especially interesting in moments of collision with moving objects.

Everybody is familiar with the everyday Doppler effect. It is an audible change in pitch. For example, it manifests itself when a fire engine signal approaches and then recedes. The observed frequency of the sound wave depends on the speed of the source and the observer. In that case, a popular aspect of the Einstein's theory has implications for the Doppler effect, especially for the light waves.

It turned out that there is a different regime between the theory of relativity and the classical wave regime. It is associated with the wave phenomena where memory affects the scattering process. They were demonstrated by a group of scientists led by Ginzburg.

They managed to drastically change the Doppler effect by recalling previous wave interactions. When the rotating dipoles are positioned to retain long-lasting memories of past interactions with the incident wave, the Doppler signature reflects asymmetric peaks in the scattering spectrum. These memories are long lasting and do not fade quickly. They influence the present and future evolution of the system under study.

The researchers called that discovered memory effect as universal. It can manifest itself in a variety of aspects associated with the waves: from optics with rotating lasers to astronomy with rotating dipoles approaching a neutron star. Although the effect is universal, not every diffuser has a long memory.

If introduced into schemes with electromagnetic applications, then it can improve the efficiency of radar identification and target classification, among other applications, for example, such as stellar radiometry. The new method, according to the researchers, will help them to understand the structure of the Universe and its evolutionary streams better.