Cosmic entanglement sudden birth: expansion-induced entanglement in hydrogen atoms

In our analysis of the expansion-induced hyperfine entanglement of the hydrogen atom, we use the standard Hamiltonian for the hyperfine structure of the ground-state atomic hydrogen. This involves introducing the electron spin operator \(\hat{S}\) and the proton spin operator \(\hat{I}\). Therefore, the effective Hamiltonian for the ground-state hyperfine structure can be expressed as \({H}_{HF}=A\hat{S}\cdot \hat{I}\). … Read more

This baby exoplanet is made of different stuff than its birth cloud

Planets can differ from the swirling envelopes of gas and dust from which they are born, astronomers have found. The revelation seems to indicate that the planet formation model favored by scientists may be overly simple. A team led by researchers from Northwestern University in Illinois made this discovery while observing a still-forming planet and … Read more