Toroidal-Moment-Possessing Quantum Hall Systems: a Quantum Intrusion into Macroscopic World

Abstract

The face of physics is a function of scale. This widespread phrase is considered as a universal truth because it reflects the experience of generations of physicists. Starting from primary school we know that the physics of macroscopic solid state systems rests on the notion that these systems consist of a great number of spatially periodic microscopic building blocks. Thus, it seems to be quite logic to expect the same properties from geometrically identical macroscopic regions of the same macroscopic system. The above statement is quite general and it is also known to be valid for the systems of a reduced dimensionality in the direction, along which they are macroscopic. However, in this work we report on a macroscopic system, which does not obey the above postulates and demonstrates specific quantum behaviour on a macroscopic length. It is conventional quantum Hall system possessing an asymmetric confining potential in presence of a tilted quantizing magnetic field. In the direction, along which the system is macroscopic, it demonstrates the following unusual properties: (i) a spatially-dependent response on a spatially-homogeneous photo-excitation that implies spontaneous breaking of translational symmetry (ii) high sensitivity of a local photo-response to the conditions of macroscopically remote local regions (iii) excitation of whole system through the excitation of its local region without an appropriate energy transfer within the system. All these properties imply the electron coherent length to be as high as the macroscopic sample length. We demonstrate that the effect revealed opens the door for an energy-free quantum communication on macroscopic distances.