English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The Bogoliubov method for the excitation spectrum of a Bose-condensed gas isgeneralized to apply to a gas with an exact large number $ N$ of particles.This generalization yields a description of the Schr\"odinger picture fieldoperators as the product of an annihilation operator $A$ for the total numberof particles and the sum of a ``condensate wavefunction'' $\xi(x)$ and a phononfield operator $\chi(x)$ in the form $\psi(x) \approx A\{\xi(x) +\chi(x)/\sqrt{N}\}$ when the field operator acts on the N particle subspace. Itis then possible to expand the Hamiltonian in decreasing powers of $\sqrt{N}$,an thus obtain solutions for eigenvalues and eigenstates as an asymptoticexpansion of the same kind. It is also possible to compute all matrix elementsof field operators between states of different N.Comment: RevTeX, 11 page

physical review. a, atomic, molecular, and optical physics/physical review, a, atomic, molecular, and optical physics

Particle-number-conserving Bogoliubov method which demonstrates the validity of the time-dependent Gross-Pitaevskii equation for a highly condensed Bose gas