Researchers Demonstrate Existence of New Form of Electronic Matter

According to the news that has been published in the journal ‘Nature’, engineers based at the University of Illinois have shown that a new form of electronic matter exists. It is called quadrupole topological insulators (QTI).

The properties exhibited by this electronic matter, QTI could bring about a wide range of possibilities in the computer field. It holds great promise in the manufacturing of low-power, robust computers and various devices, that are all defined at the atomic scale.

The topological insulators (TI) are basically electrical insulators on the inside but are conductors along the boundaries. This unique property exhibited by the topological insulators makes them a special type of electronic matter.

A group of electrons form their own phases within the materials. This can be either in the solid, liquid and gas phase, as is seen in water. They can also form an uncommon phase like a topological insulator.

What is this new phase of Electronic Matter? 

The new form of electronic matter is the Quadrupole Topological Insulator. According to theoretical physics, some of the topological insulators have an electrical property known as quadrupole moment.

As we see in a material, the electrons carry a charge. In the process, the material becomes bipolar, that is it contains the positive as well as the negative charge.

Now, in a higher order class of material, we get a quadrupole which is a coupling of two positive and two negative charges. In crystals, the electrons can arrange themselves in such a way that they can give rise to high-order multipoles besides the usual dipole units. In the case of multipoles, four or eight charges are collectively arranged in a unit. The basic forms of multipoles are the quadrupoles wherein two positive and two negative charges are coupled together in a unit.

An analog of a QTI was shown by the researchers of the University of Illinois. They demonstrated it by using a special material from printed circuit boards.

Each circuit has a square of four identical resonators or devices that can absorb electromagnetic radiation at a particular frequency. The boards were positioned in a grid to form the crystal analog.
Each of these resonators behaves like an atom and the connections between the resonators act as bonds between these atoms.

The system is then subjected to microwave radiation to measure the amount that has been absorbed by each of the resonators. This in turn will indicate the behavior of the electrons in an analogous crystal. If the microwave radiation absorbed by a resonator is more, then there are higher chances of finding an electron on the corresponding atom.

In the above experiment it was inferred that the corners of the connected resonators absorbed the microwave radiation at a specific frequency whereas the rest of the units did not do so. The researchers then separated the bottom row from the grid and on subjecting it to the microwave radiation, it was noticed that the next highest rows showed the topological effects on absorbing the radiation.

They concluded that the edges of a QTI are not conductive unlike that seen in a TI. It was only the corners which are active and they correspond to the four localized point charges that form the quadrupole moment.

On measuring the amount of microwave radiation each of the resonators absorbed in the QTI, it was confirmed that the resonant states was in a particular frequency range and localized in the four corners. This shows the existence of predicted protected states that would be filled up by electrons that would in turn form four corner charges.

With the experiment conducted, scientists are beginning to understand the possibilities of the new electronic matter and its application. As of now, the physicists can predict that the new form of electronic matter exists, but no material has been found to have these properties.

Integrated quantum Optical Circuits Soon a Reality

Scientists are on the Verge of Enabling Chip with Quantum Optical Circuit for Information Processing

A group of researchers working on the quantum nano photonics has come up with a method which would result in the development of new age quantum optical circuit. Our world of technology is going through a breakneck pace of advancement which is happening almost every given second across the varied fields. One such field is filled with quantum computers and networks which are designed to work in a way better than our conventional computers and networks.

Our traditional computing devices and networks works by encoding information in binary bits while the quantum computing makes use of quantum bits which can contain two vales at the same time. Quam Computers thus have the ability to process a larger amount of information with lesser number of calculation steps. This functionality makes them a huge potential for the creating energy efficient computation along with sensing and securing the communication in near future.

Developing Quantum Optical Circuit

 

In order to develop quantum computers researchers will have to get a working circuit to power it. So far researchers have failed to create an effective integrated quantum circuits but it has been finally done by the KTH researchers. This team made use of the novel nano-manipulation technique in order to transfer the selected single photon emitters right into the nanowire present on a silicon chip. This process was utilized to carefully build a highly integrated optical circuit which has the ability to filter single photons as well as multiplex them. This quantum optical circuit makes use of multiple quantum dots in order to generate light in varied colours thereby encoding different information on the same chip.

Developing a fully functional quantum optical circuit it was a challenge to build all of its components deterministically. In other words each and every component of this unique circuit is simply designed and optimized a single specific task. Researchers had to work in a tiresome fashion with no room of error at all in order to get right set of characteristics embedded in its exact location on the circuit.

Achievement And Future Application Of Quantum Optical Circuit

This team of researchers has been able to get achievement associated with their name for years to come. Their work has also resulted in the creation of a hybrid approach which helps in combining two very different semiconductor technologies. Essentially they had combined III-IV technology using their nanowire-based emitters with the silicon technology to create an integrated quantum optical circuit. As stated earlier no one has been able match this feat before using a hybrid integration utilizing just the nanowires.

This intricate process had made them  successful at generating and adding filtered single photons right on the silicon chipset without making use of any external components. Their great invention and complete breakdown of the methods and results will be published shortly in a popular scientific journal named Nature Communications. This also paves the way for the scientists to develop effective quantum circuits in future for specific purposes.