Topic
Entanglement and quantum information research, explained
10 open-access entanglement and quantum information studies, each with a flashcard deck and a quiz.
- Can quantum bits in two cities be entangled over real fibre?
Two diamond-based quantum bits 10 kilometres apart were entangled through ordinary deployed telecom fibre, with the success signalled in real time so the shared state was ready to use.
- Can quantum teleportation run fast over city-scale fibre?
Researchers teleported single-photon quantum states across a campus fibre network several times per second with fidelity well above what any classical method could reach.
- Can measuring two quantum copies together beat measuring them one by one?
Measuring two copies of a noisy qubit jointly with an entangling circuit estimated two rotation angles more precisely than any one-at-a-time measurement can, on real quantum computers.
- Can sound waves carry entangled quantum states across a chip?
Single quanta of sound travelling along a tiny silicon waveguide were shown to carry entanglement, passing a Bell test with a partner photon.
- Can entangled photons measure the Earth's rotation?
Pairs of entangled photons sent around a giant fibre loop detected Earth's spin and picked up twice the phase shift that single photons did, as quantum theory predicts.
- Can special quantum states avoid scrambling and keep entanglement?
In a chaotic ladder of superconducting qubits, certain specially built states keep oscillating and stay structured instead of thermalizing, and the entanglement of one family of them can be dialled with disorder.
- Can looping around an exceptional point switch entangled states?
Steering a lossy photonic system around an exceptional point converts one entangled Bell state into another, with the result set by the loop's direction and robust to small errors.
- Can one wavelength carry entanglement to three partners at once?
Pumping a chip-scale ring resonator with two lasers let one wavelength channel be entangled with three others, halving the channels needed to fully connect four quantum-network users.
- Can noise be turned into a helper in quantum teleportation?
By first entangling photons' polarisation with their frequency in a tailored way, the researchers made later noise undo the scrambling, so teleported quantum states came out with high fidelity instead of being ruined.
- Can a trained 'black box' measurement detect photon entanglement?
A simple linear model trained on the outputs of an imperfect, uncalibrated optical setup learned to certify entanglement of photon pairs, even when it was only ever trained on unentangled states.