Quantum grains lined in a surface as the basis for an error-tolerant quantum processor. Credit: Uni Innsbruck / Harald Ritsch
Even computers can make mistakes. Already minor interruptions alter stored information and corrupt products. That is why computers are continually using methods to correct such errors.
In quantum computing, the error vulnerability can be reduced by storing quantum information in more than one quantum grain. These logical oceanic beats are less sensitive to errors.
In the last few years, theorists have developed many error correction codes and optimized them for different tasks. “The most promising codes in quantum error correction are those that are defined on a two-dimensional surface,” explained Thomas Monz of the Department of Experimental Physics at the University of Innsbruck. “This is because the physical structure of conventional quantum computers can be well mapped through such bolts. ”
With the help of the codes, logical quantum parts can be spread over a number of quantum objects. The quantum physics from Innsbruck has now succeeded for the first time in engaging in two quantum pulses coded in this way. Engaging two quantum beats is an important resource of quantum computers, giving them a performance advantage over classical computers.
A type of quantum sewing machine
For their experiment, the physicists use a ten-ion trap quantum computer. Into these ions the logical quantum particles are encoded. Using a method that scientists refer to as ‘lattice surgery’, two logical nodules encoded on a surface can be joined together. “A larger new qubit is created from the qubits sewn together in this way,” explained Alexander Erhard of the Innsbruck team. At the same time, a large logical qubit can be separated into two separate logical chunks by lattice surgery.
Compared to the normal operations between two logical knuckles, knee surgery only requires work across the end of the encoded qubits, not on the entire surface. “This reduces the number of operations required to interact between two coded blocks,” explained theoretical physicist Nicolai Friis and Hendrik Poulsen Nautrup.
Leading technology for crack-tolerant oceanic computers
Lattice surgery is considered to be one of the main methods for the operation of defective quantum computers. Using knee surgery, physics will be led by Thomas Monz and Rainer Blatt, along with theoretical physicists Hendrik Poulsen Nautrup and Hans Briegel from the Department of Theoretical Physics at the University of Innsbruck and Nicolai Friis from the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences in Vienna, has now shown that they are intertwined between two nuggets of code.
This is the first experimental performance of nonclassical correlations between topologically coded qubits. Additionally, the researchers were able to demonstrate for the first time the teleportation of quantum states between two encoded angles.
Information: 13 January 2021, Nature.
DOI: 10.1038 / s41586-020-03079-6
The research was financially supported by the Austrian Science Fund FWF and the FFG Research Incentive Group as well as the EU.