%0 Journal Article %J Comm. Math. Phys. 221 (2001) 161-168 %D 2001 %T Instantons on the Quantum 4-Spheres S^4_q %A Ludwik Dabrowski %A Giovanni Landi %A Tetsuya Masuda %X We introduce noncommutative algebras $A_q$ of quantum 4-spheres $S^4_q$, with $q\\\\in\\\\IR$, defined via a suspension of the quantum group $SU_q(2)$, and a quantum instanton bundle described by a selfadjoint idempotent $e\\\\in \\\\Mat_4(A_q)$, $e^2=e=e^*$. Contrary to what happens for the classical case or for the noncommutative instanton constructed in Connes-Landi, the first Chern-Connes class $ch_1(e)$ does not vanish thus signaling a dimension drop. The second Chern-Connes class $ch_2(e)$ does not vanish as well and the couple $(ch_1(e), ch_2(e))$ defines a cycle in the $(b,B)$ bicomplex of cyclic homology. %B Comm. Math. Phys. 221 (2001) 161-168 %I Springer %G en_US %U http://hdl.handle.net/1963/3135 %1 1198 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-17T09:47:38Z\\nNo. of bitstreams: 1\\n0012103v2.pdf: 128667 bytes, checksum: 86c8b564b4eb5008fad8371fcfd5f265 (MD5) %R 10.1007/PL00005572