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For many years, quantum computers were not much more than an idea. Today, companies, governments and intelligence agencies are investing in the development of quantum technology. Robert König, professor for the theory of complex quantum systems at the TUM, in collaboration with David Gosset from the Institute for Quantum Computing at the University of Waterloo and Sergey Bravyi from IBM, has now placed a cornerstone in this promising field.

A RUDN physicist demonstrated how to describe the shape of any symmetrical wormhole—a black hole that theoretically can be a kind of a portal between any two points in space and time—based on its wave spectrum. The research would help understand the physics of wormholes and better identify their physical characteristics. The article was published in the Physics Letters B journal.

Modern concepts of the universe provide for the existence of wormholes—unusual curvatures in space and time. Physicists imagine a wormhole as a black hole through which one can see a distant point of the universe in four dimensions. Astrophysicists are still unable to determine the shape and sizes of black holes precisely, let alone theoretical wormholes. A RUDN physicist has now demonstrated that the shape of a wormhole can be calculated based on observable physical characteristics.

In practice, physicists can observe only indirect properties of wormholes, such as red shift—a downward shift in the frequency of gravitational waves in the course of moving away from an object. Roman Konoplya, a research assistant from the RUDN Institute of Gravitation and Cosmology, the author of the work, used quantum mechanical and geometrical assumptions and showed that the shape and mass of a wormhole can be calculated based on the red shift value and the range of gravitational waves in high frequencies.

Scientists at TU Wien, the University of Innsbruck and the ÖAW have for the first time demonstrated a wave effect that can lead to measurement errors in the optical position estimation of objects. The work now published in Nature Physics could have consequences for optical microscopy and optical astronomy, but could also play a role in position measurements using sound, radar, or gravitational waves.

With modern optical imaging techniques, the position of objects can be measured with a precision that reaches a few nanometers. These techniques are used in the laboratory, for example, to determine the position of atoms in quantum experiments.

“We want to know the position of our quantum bits very precisely so that we can manipulate and measure them with laser beams,” explains Gabriel Araneda from the Department of Experimental Physics at the University of Innsbruck.

If you replace classical bits with qubits, though, you go back to only needing one per spin in the system, because all the quantum stuff comes along for free. You don&s;t need extra bits to track the superposition, because the qubits themselves can be in superposition states. And you don&s;t need extra bits to track the entanglement, because the qubits themselves can be entangled with other qubits. A not-too-big quantum computer— again, 50–100 qubits— can efficiently solve problems that are simply impossible for a classical computer.

These sorts of problems pop up in useful contexts, such as the study of magnetic materials, whose magnetic nature comes from adding together the quantum spins of lots of particles, or some types of superconductors. As a general matter, any time you&s;re trying to find the state of a large quantum system, the computational overhead needed to do it will be much less if you can map it onto a system of qubits than if you&s;re stuck using a classical computer.

So, there&s;s your view-from-30,000-feet look at what quantum computing is, and what it&s;s good for. A quantum computer is a device that exploits wave nature, superposition, and entanglement to do calculations involving collective mathematical properties or the simulation of quantum systems more efficiently than you can do with any classical computer. That&s;s why these are interesting systems to study, and why heavy hitters like Google, Microsoft, and IBM are starting to invest heavily in the field.

Continue reading “What Is A Quantum Computer? The 30,000 Foot Overview” »

A qubit by any other name would still confound as succinctly. Poet and Professor Amy Catanzano seeks to unveil the mysteries of quantum physics with poetry.

Can the origin of life be explained with quantum mechanics? And if so, are there quantum algorithms that could encode life itself?

We’re a little closer to finding out the answers to those big questions thanks to new research carried out with an IBM supercomputer.

Encoding behaviours related to self-replication, mutation, interaction between individuals, and (inevitably) death, a newly created quantum algorithm has been used to show that quantum computers can indeed mimic some of the patterns of biology in the real world.

Continue reading “Scientists Just Created Quantum Artificial Life For The First Time Ever” »

A novel technique that nudges single atoms to switch places within an atomically thin material could bring scientists another step closer to realizing theoretical physicist Richard Feynman’s vision of building tiny machines from the atom up.

Superconducting quantum microwave circuits can function as qubits, the building blocks of a future quantum computer. A critical component of these circuits, the Josephson junction, is typically made using aluminium oxide. Researchers in the Quantum Nanoscience department at the Delft University of Technology have now successfully incorporated a graphene Josephson junction into a superconducting microwave circuit. Their work provides new insight into the interaction of superconductivity and graphene and its possibilities as a material for quantum technologies.

The essential building block of a quantum computer is the quantum bit, or qubit. Unlike regular bits, which can either be one or zero, qubits can be one, zero or a superposition of both these states. This last possibility, that bits can be in a superposition of two states at the same time, allows quantum computers to work in ways not possible with classical computers. The implications are profound: Quantum computers will be able to solve problems that will take a regular computer longer than the age of the universe to solve.

There are many ways to create qubits. One of the tried and tested methods is by using superconducting microwave circuits. These circuits can be engineered in such a way that they behave as harmonic oscillators “If we put a charge on one side, it will go through the inductor and oscillate back and forth,” said Professor Gary Steele. “We make our qubits out of the different states of this charge bouncing back and forth.”

Continue reading “Ballistic graphene Josephson junctions enter microwave circuits” »

Urmila Mahadev spent eight years in graduate school solving one of the most basic questions in quantum computation: How do you know whether a quantum computer has done anything quantum at all?