It might all sound like a sci-fi concept, but building quantum networks is a key ambition for many countries around the world. Recently the US Department of Defense (DoE) published the first blueprint of its kind, laying out a step-by-step strategy to make the quantum internet dream come true, at least in a very preliminary form, over the next few years. The US joined the EU and China in showing a keen interest in the concept of quantum communications. But what is the quantum internet exactly, how does it work, and what are the wonders that it can accomplish? WHAT IS THE QUANTUM INTERNET?
Three nodes that can store and process quantum bits were linked to create the world's first rudimentary quantum network. Researchers in the Netherlands have successfully connected three separate quantum processors in what is effectively the world's first multi-node quantum network. This paves the way for a large-scale quantum internet that governments and scientists have been dreaming up for decades. QuTech, a quantum research institute based in Delft, has published new work in which three nodes that can store and process quantum bits (also called qubits) were linked. This, according to the QuTech researchers, is the world's first rudimentary quantum network.
"The tantalizing promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor. A fundamental challenge is to build a high-fidelity processor capable of running quantum algorithms in an exponentially large computational space. Here, we report using a processor with programmable superconducting qubits to create quantum states on 53 qubits, occupying a state space 253 1016. Measurements from repeated experiments sample the corresponding probability distribution, which we verify using classical simulations. While our processor takes about 200 seconds to sample one instance of the quantum circuit 1 million times, a state-of-the-art supercomputer would require approximately 10,000 years to perform the equivalent task. This dramatic speedup relative to all known classical algorithms provides an experimental realization of quantum supremacy on a computational task and heralds the advent of a much-anticipated computing paradigm." It is fascinating to consider what will happen next in the intersection of quantum information and artificial intelligence. It is also hard to tell where it will lead, perhaps a new computing paradigm?
No, quantum computing did not come of age with Google's Sycamore, a 53-qubit computer solving in 200 seconds a problem that would take even a supercomputer 10,000 years. Instead, it is the first step, showing that a functional computation can be done with a quantum computer, and it does indeed solve a special class of problems much faster than conventional computers. This is not that quantum computers have now superseded classical computers. The hype of quantum supremacy is misleading as it is based on a very narrow definition quantum supremacy; quantum supremacy is one quantum computer beating all classical computers for one specially constructed task. The bad news -- for the science fiction enthusiasts -- is that it is not going to replace our current computers but will be useful only for a special class of problems.
"The quantum threat is basically going to destroy the security of networks as we know them today," declared Bruno Huttner, who directs strategic quantum initiatives for Geneva, Switzerland-based ID Quantique. No other commercial organization since the turn of the century has been more directly involved in the development of science and working theories for the future quantum computer network. Quantum computers offer great promise for cryptography and optimization problems. ZDNet explores what quantum computers will and won't be able to do, and the challenges we still face. One class of theory involves cryptographic security.