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Category: quantum physics – Page 964

Researchers demonstrate teleportation using on-demand photons from quantum dots

https://paper.li/e-1437691924#/

A team of researchers from Austria, Italy and Sweden has successfully demonstrated teleportation using on-demand photons from quantum dots. In their paper published in the journal Science Advances, the group explains how they accomplished this feat and how it applies to future quantum communications networks.

Scientists and many others are very interested in developing truly —it is believed that such networks will be safe from hacking or eavesdropping due to their very nature. But, as the researchers with this new effort point out, there are still some problems standing in the way. One of these is the difficulty in amplifying signals. One way to get around this problem, they note, is to generate photons on-demand as part of a quantum repeater—this helps to effectively handle the high clock rates. In this new effort, they have done just that, using semiconductor .

Prior work surrounding the possibility of using has shown that it is a feasible way to demonstrate teleportation, but only under certain conditions, none of which allowed for on-demand applications. Because of that, they have not been considered a push-button technology. In this new effort, the researchers overcame this problem by creating quantum dots that were highly symmetrical using an etching method to create the hole pairs in which the quantum dots develop. The process they used was called a XX (biexciton)–X (exciton) cascade. They then employed a dual-pulsed excitation scheme to populate the desired XX state (after two pairs shed photons, they retained their entanglement). Doing so allowed for the production of on-demand single photons suitable for use in teleportation. The dual pulsed excitation scheme was critical to the process, the team notes, because it minimized re-excitation.

MIT Researchers Can Shrink Objects to Nanoscale

MIT researchers invented a method of shrinking objects to the nanoscale.

The team can generate structures one-thousandth the volume of the original using a variety of materials, including metals, quantum dots, and DNA.

Existing techniques—like etching patterns onto a surface with light—work for 2D nanostructures, but not 3D. And while it’s possible to make 3D nanostructures, the process is slow, challenging, and restrictive.

Scientists Report Teleportation of Physical Objects From One Location To Another

The concept of teleportation comes primarily from science fiction literature throughout human history, but things are changing. It’s 2015 and developments in quantum theory and general relativity physics have been successful in exploring the concept of teleportation for quite some time now.

Today, numerous teleportation breakthroughs have been made. One example is the work of Professor Rainer Blatt, at the University of Innsbruck. They were successfully able to perform teleportation on atoms for the first time, their work was published in the journal Nature. They were able to transfer key properties of one particle to another without using any physical link. In this case, teleportation occurred in the form of transferring quantum states between two atoms, these include the atom’s energy, motion, magnetic field and other physical properties. This is possible due to the strange behavior that exists at the atomic scale, known as entanglement. It’s what Einstein referred to as a “spooky action.”

Another study was published by a team of University of Queensland physicists in the journal Nature in 2013 demonstrating the successful teleportation with solid state systems. A process by which, again, quantum information can be transmitted from one place to another without sending a physical carrier of information. This is the same concept, and is made possible through the phenomenon of entanglement.

A new type of quantum computer has smashed every record

IonQ was founded on a gamble that ‘trapped ion quantum’ computing could outperform the silicon-based quantum computers that Google and others are building. As of right now, it does. IonQ has constructed a quantum computer that can perform calculations on a 79-qubit array, beating the previous king Google’s efforts by 7 qubits.

Their error rates are also the best in the business, with their single-qubit error rate at 99.97% while the nearest competitors are around the 99.5 mark, and a two-qubit error rate of 99.3% when most competitors are beneath 95%. But how does it compare to regular computers?

According to IonQ, in the kinds of workloads that quantum computers are being built for, it’s already overtaking them. The Bernstein-Vazirani Algorithm, a benchmark IonQ is hoping will take off, tests a computer’s ability to determine a single encoded number (called an oracle) when the computer can only ask a single yes/no question.

If energy can’t be created, where did it come from in the first place?

We’re taught at school that energy can’t be created, merely converted from one form to another. But at the birth of the Universe – that is, everything – the energy needed for the Big Bang must have come from somewhere. Many cosmologists think its origin lies in so-called quantum uncertainty, which is known to allow energy to emerge literally from nowhere. What isn’t clear, however, is why this cosmic energy persisted long enough to drive the Big Bang.

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