Quantum Simulators

New Quantum Simulator Raises the Bar for the Competition 

Soon, scientists might be able to perform calculations on completely new level using the new model of quantum computer; previously inaccessible areas of material science could finally open up to us. Group of researchers at the National Institute of Standards and Technology was able to create a quantum simulator that exceeds the best quantum computers of today by far. The new model is comprised of hundreds of qubits located on a single layer of crystal which are made to behave uniformly. The best prototypes built so far can boast up to eight cubits. Today, we are not yet able understand most of quantum behavior. We could not understand the nature of electricity hundred years ago either, yet it did not stop us from using it. We are not completely sure how quantum state of one particle can be precisely replicated by the second particle located far away - the phenomenon called teleportation - but Chinese scientists were able to set new, 60 miles record this year.


Physical interactions between particles of such small size are difficult to understand andstudy. For example, researchers still cannotsettle on a definition of the ground state of the hydrogen molecule - apparently simple question. Modern computers do not have enough processing power to reproduce quantum simulator bigger than few qubits in size; scientists need quantum computer to design real simulator! Quantum systems are very complex because one qubit can have very large degrees of freedom, and their complexity exponentially increases with the number of qubits involved. A rule of thumb is that the number of qubits in the system must be equal to the quantity of potential states the qubit can take, and current prototypes do not quite make the grade.

What is Quantum Simulator?

A quantum simulator usually is comprised of number of atoms, arranged in a uniform geometry and forced to interact in a predictable way by the magnetic field and temperature. The position (configuration, or spin) of each atom is described by the description of the state of the energy of that atom and is a highly complicated value requiring lots of computing power. Once, the initial state of the simulator is set, researchers begin to observe the development of the system by applying magnetic field and temperature to the unit. By observing the total magnetic fields of all spins in the simulator scientists control its behavior.


NIST Project

Research team from NIST have simulator to the next level. They have trapped hundreds of beryllium ions in one spot forming a triangular shape. Flat beryllium crystal is less than one millimeter wide in size and only one atom thin. It is held in place by a strong magnetic field perpendicular to its surface. As you can see on the photo above, the ions are colored in one, blue color, indicating that all the atoms are in the same state of spin. Additionally, individual atoms can be controlled as well as pairs of ions at a time. This adds a dimension to the level of control over the simulator.



In order to keep the crystal at near absolute zero temperature laser beams are used. Interaction and changes in the qubits are also caused by the laser and microwave pulses. Right now, researchers are only trying to gain full control over few-qubit simulator structure but future plans include engineering mathematically identical materials, neural networks and behaviors. Scientists believe that quantum simulator is able to reproduce exact replica of any system, though physical appearance of the copy could differ from the original. Industries that might be soon using simulation include neuroscience, manufacturing, information technology and many others. Any problem, studied using exact replica of the original can be solved without a loss to the original.


References: National Institute of Standards and Technology, Technology Review, Cornell University Library.