## Quantum simulation with hundreds of quibits

**12 April 2012**

An international team including the University of Sydney's Dr Michael Biercuk have developed a sub millimetre sized ion-crystal that enables a computer to perform analogue calculations that currently stump the world's most powerful supercomputers. The results were published in the journal Nature on 26 April 2012."Computing technology has taken a huge leap forward using a crystal with just 300 atoms suspended space in a two-dimensional triangular crystal," said Dr Biercuk, from the University's School of Physics and ARC Centre of Excellence for Engineered Quantum Systems.

"The system we have developed has the potential to perform calculations that would require a supercomputer larger than the size of the known universe - and it does it all in a diameter of less than a millimetre," said Dr Biercuk.

The team Dr Biercuk worked with, including scientists from the US National Institute of Standards and Technology, Georgetown University in Washington, North Carolina State University and the Council for Scientific and Industrial Research in South Africa, has produced a specialised kind of quantum computer known as a 'quantum simulator'.

This quantum simulator acts as a quantum analogue computer that models a problem to be solved by modelling the quantum systems rather than calculate them.

"By engineering precisely controlled interactions and then studying the output of the system, we are effectively running a 'program' for the simulation," said Dr Biercuk. The work was able to model well known interactions with excellent agreement.

"The projected performance of this new experimental quantum simulator eclipses the current maximum capacity of any known computer by an astonishing 10 to the power of 80. That is 1 followed by 80 zeros, in other words 80 orders of magnitude, a truly mind-boggling scale."

The work smashes previous records in terms of the number of elements working together in a quantum simulator, and therefore the complexity of the problems that can be addressed.

The teams contribution to the area of quantum simulation is the relative simplicity of the method used to create the naturally occurring lattice as well as the number of particles in the lattice, therefore the number of quibits.

Ever since Nobel Prize winner Richard Feynman highlighted the potential of quantum computing in the 1980s, scientists have been attempting to build quantum computers capable of solving some of the largest and most complex problems. Special-purpose quantum simulators have tremendous potential to solve a variety of challenging problems in materials science, chemistry, and biology, with much greater efficiency than conventional computers.

"Many properties of natural materials governed by the laws of quantum mechanics are very difficult to model using conventional computers. The key concept in quantum simulation is building a quantum system to provide insights into the behaviour of other naturally occurring physical systems."

"In our case, we are studying the interactions of spins in the field of quantum magnetism - a key problem that underlies new discoveries in materials science for energy, biology, and medicine," said Dr Biercuk.

"For instance, we hope to study the spin interactions predicted by models for high-temperature superconductivity - a physical phenomenon that has yet to be explained, but has the potential to revolutionise power distribution and high-speed transport."

The experimental device provides exceptional new capabilities which allow the researchers to engineer interactions which mimic those found in natural materials.

Remarkably they can even realise interactions that are not known to be found in nature, engineering totally new forms of quantum matter.

Click here for the link to the University of Sydney article.

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