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تسجيل مستخدم جديدThe $ u={1over2}$ Landau level: Half-full or half-empty?
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We show here that an extension of the Hamiltonian theory developed by us over the years furnishes a composite fermion (CF) description of the $ u =frac{1}{2}$ state that is particle-hole (PH) symmetric, has a charge density that obeys the magnetic translation algebra of the lowest Landau level (LLL), and exhibits cherished ideas from highly successful wave functions, such as a neutral quasi-particle with a certain dipole moment related to its momentum. We also a provide an extension away from $ u=frac{1}{2}$ which has the features from $ u=frac{1}{2}$ and implements the the PH transformation on the LLL as an anti-unitary operator ${cal T}$ with ${cal T}^2=-1$. This extension of our past work was inspired by Son, who showed that the CF may be viewed as a Dirac fermion on which the particle-hole transformation of LLL electrons is realized as time-reversal, and Wang and Senthil who provided a very attractive interpretation of the CF as the bound state of a semion and anti-semion of charge $pm {eover 2}$. Along the way we also found a representation with all the features listed above except that now ${cal T}^2=+1$. We suspect it corresponds to an emergent charge-conjugation symmetry of the $ u =1$ boson problem analyzed by Read.
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