American physicists experimentally confirmed the dynamic process of fermionization one-dimensional bosonic gas. Forcing bars ultralong bosons to expand in one direction, scientists observe the change in the pulse distribution from the bosonic species to germinoma. The results of a study published in the journal Science.
All particles can be divided into two groups: bosons and fermions. The criterion for such division is the value of the spin quantum number characterizing the own moment of momentum of a particle. If the spin of your particles is determined by an integer is a boson, and if half-integer — fermion. The vast majority of cases, bosons and fermions behave in the opposite way. Obeying the Pauli principle, two or more identical fermions cannot simultaneously be in the same quantum state. To describe a large number of identical fermions applied statistics Fermi—Dirac. Bosons, unlike fermions, obey the statistics of Bose—Einstein, which allows for finding an unlimited number of identical particles in the same quantum state. At low temperatures a gas of bosons becomes condensate Bose—Einstein, and hermiony gas — Fermi-liquid.
In 2004, physicists showedthat if using the optical traps to get cold bosons to move only along one line, they have the properties of fermions. The laws of physics still do not prohibit the bosons to be in the same quantum state, however, the interaction between them makes the process energetically unfavorable. In the end, the bosons occupy different quantum States, and one-dimensional spatial distribution of bosons looks like a distribution of noninteracting fermions, such a process physicists call periodizacii. Work 2004 is limited to the study of fermionization in the equilibrium state.
A group of scientists under the leadership of Joshua Wilson (Joshua M. Wilson) from the University of Pennsylvania has studied the dynamic process of fermionization bosonic gas of cold rubidium atoms. Her back in 2005 was theoretically predicted by one of the authors of the study, RIGOL Marcos (Marcos Rigol). He showed that the expansion of the lattice bosons in one direction generates a velocity distribution similar to germinoma. To confirm the hypothesis of rigola, scientists have formed an array of ultracold rubidium atoms with optical lattices, having a one-dimensional chain of atoms with a negligible tunneling between them. In this equilibrium state wave function of bosons with a precision of up to constant repeats versionnow wave function. The energy and spatial distribution of two gases is also similar. But the velocity distribution remains different.
When you disable one of the components of the optical trap, the bosons begin a one-dimensional extension. Using the method of-flight (TOF) of physics got the momentum distribution of bosons, which, according to theoretical predictions smoothly into hermionie.