Space and Physics
PUBLISHED
Privacy on the internet is a complex affair. It can protect and it can endanger. Anonymity can be a sword to harass people with, and at the same time, virtual private networks (VPNs) allow people to bypass state censorship and unjust laws. On a quantum internet, where the information passes through quantum computers and other quantum devices, neither could happen. One’s location can always be confirmed.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.Quantum computers are the next big leap in computer science. These devices, which are mostly still in their infancy, have the ability to perform computations that are virtually impossible on even the most powerful supercomputers. While regular computers use binary bits of information, the 1s and the 0s, quantum computers use quantum bits, or qubits. Qubits exist as 1, 0, and a superposition of the two values.
Superposition is one of the exciting fundamental properties in quantum mechanics. Those qubits can be 1 and 0 at the same time. A regular bit is like a switch that is either on or off. Not so in the quantum world, where things can be both on and off at the same time.
Another important quantum property that comes into play is entanglement. If two particles are entangled, they are placed in such a quantum state that no matter their distance, measuring the property of one will affect the property of the other.
Albert Einstein did not like this at all. He called it "spooky action at a distance". He believed in this principle of local realism and that there existed some "hidden variables" that affected the experiment. This has been tested in many ways using the Bell inequality test. Versions of it have even included using 100,000 people playing a video game. The result? There is no faster-than-light communication or anything beyond our physics. Quantum mechanics is fine with entanglement, and entangled particles are a single system that shouldn’t be considered independently.
Entanglement is particularly important with the idea of a quantum internet, as it allows information to be sent securely in a way that can’t be hacked with a normal system. On the internet today, you can’t be certain where any other person is. A new approach, using a specific type of Bell test, can be used to perform a quantum position verification. This approach, which has been described in a study that is yet to be peer-reviewed, instead allows you to make sure that you know who’s at the other end of your communications.
In the experimental demonstration, the team places a remote party against adversaries. The remote party would measure certain properties of entangled photons at the same time as the sender, and over several times, using the Bell test, they can verify the strong correlation.
The adversaries are weakly entangled but possess unlimited quantum computation and communication capabilities. Still, if they were to intercept a photon not meant for them, the test would not reveal that strong correlation, giving them away. This approach shows a protocol that is device-independent, with no need for dedicated hardware.
The work was presented last month at the American Physical Society’s Global Physics Summit, and a preprint is posted to arXiv.
[H/T: ScienceNews]
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