Quantum Cat Made of 120 Photons ⚡ экспресс
The study focuses on generating large "cat states" using the dynamic invariant of hybrid qubit-boson systems under time-dependent Hermitian or non-Hermitian Hamiltonians. The formalism of universal quantum control is employed, where the system dynamics are analyzed in an auxiliary representation via a unitary transformation conditioned on the qubit state. The Heisenberg equation for the dynamic invariant imposes constraints on the Hamiltonian, encoding controlled evolution. When the qubit is prepared in a balanced superposition, the bosonic mode deterministically evolves from the vacuum state to a cat state with an average photon number exceeding 120. In the Hermitian case, generation is perfect; in the non-Hermitian case, fidelity exceeds 0.962. The method is also applicable to creating large squeezed and four-component cat states. This work advances the theory of universal quantum control to hybrid discrete-continuous systems.
The quantum cat is a state of light proposed by Schrödinger: photons behave like a spinning coin, seen as both heads and tails at once. Physicists have created such a 'coin' from 120 photons, racing at the speed of light in a light trap. Usually, a large system quickly collapses into one option due to increasing disorder (entropy).
The solution proved elegant: a quantum switch (qubit) was coupled with the light and a mathematical trick was applied that naturally maintains balance. Even with noise, accuracy exceeded 96%, and without noise the method is flawless. Astonishingly, the previous record of 40 photons has been tripled. Such large cats will help probe the boundary between quantum wonders and the familiar world, and also serve as ultra-sensitive sensors and the basis for fault-tolerant quantum computers, building on the work of von Neumann. The assessment of duality comes from a special technique invented by Wigner.
🎯 The previous record for cat light was about 40 photons. The new result triples that number.
🎬 In 'The Quantum Thief' by Hannu Rajaniemi, quantum states store identities—large cat states could be a step toward such exotica.