Light Moving In Fourth Dimension Observed During Quantum Hall Experiment.
In our physical world, we can perceive three dimensions and one extra dimension of time as we move through the Universe.
But two recent quantum experiments have for the first time shown the existence of a fourth spatial dimension.
The teams of scientists from the U.S. and Europe have shown that, in addition to the conventional three-axis where an object can move up-down, left-right or forward-backward to an observer, there exists a fourth spatial dimension which could introduce new directions of motion.
The discovery was made by studying the results of two quantum hall experiments. "The quantum Hall effect" occurs when the motion of an electron in a material is restricted to only 2D. When electrons are confined to two dimensions, and a magnetic field passes through perpendicularly, some of the system's electrical properties become restricted to multiples of exact number values.
During this effect, it is observed that electrons can only move in well-defined topological pathways that are predetermined. For particular strengths of the magnetic field, the electric current can only flow along the edges of the material. This effect, which was observed 20 years ago, was said to be similar to what would happen to particles in the fourth-dimension.
Oded Zilberberg, ETH researcher, and a professor at the Institute for Theoretical Physics overlooked the two experiments that provided the data for the discovery. By placing together two specially designed 2D setups to study the quantum Hall effect, they were able to catch a glimpse of this fourth spatial dimension.
The team used specially designed topological pumps that helped modulate a specific parameter of the physical system in which the quantum Hall effect was observed. This causes quantum states to change in a pre-determined way. This change, the team noted, was analogous to how they expected the system to react when it was moving in an additional spatial dimension.
The 2D system immediately became a 4D system.
This was not just a flash in the pan either. A team of physicists from Penn State University and the University of Pittsburgh applied the idea birthed by Zilberberg by burning a two-dimensional array of waveguides into a 15-centimeter-long glass block using laser beams.
These waveguides were cut into the glass in random pathways, such that the distances between them varied along the glass block at different points. As the distances between the waveforms changed, the light waves (lasers) moving through the waveguides could jump easily to a neighboring waveguide.
As the team experimented with different waveguides, they found that they acted as topological pumps. The light was passed through the glass block and through the various waveforms. They recorded the light that emerged after passing through the glass. The found the edge state particles of the previously theoretically proven fourth dimension in the quantum Hall effect. Light from the edge of the lattice became directly visible, which showed the researchers the particles moving through the fourth dimension.
So what's the practical use of all this? "Right now, those experiments are still far from any useful application," Zilberberg admits.
But scientists now have an idea of what to study when it comes to exploring the fourth dimension. They can study quasicrystals in metallic alloys, which have no discernible pattern when viewed in 3D space but when one looks at them in higher virtual dimensions, they actually exhibit regular patterns.
The team feels that this could aid the world's study of string theory in which higher dimensions are just compressed in such a way that only our normal three-dimensional world exists.
A four-dimensional space or 4D space has been derived mathematically years ago. The concept is just an extension of the existing three-dimensional or 3D space all humans see. This 3D space we share is seen as the simplest possible generalization of the space around us.
The three-axis are used to describe the sizes or locations of objects we see in the everyday world and also helps us place them spatially. For example, the volume of a rectangular box is found by measuring its length (often labeled x), width (y), and depth (z) which are the three dimensions of the object, whereas a 2D rectangle uses only its length and breadth. The geometry of four-dimensional space is much more complex than that of three-dimensional space due to the extra degree of freedom.
This report has been updated with corrections.