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In this work we introduce a new notion of expansion in higher dimensions thatis stronger than the well studied cosystolic expansion notion, and is termed{\em Collective-cosystolic expansion}.  We show that tensoring two cosystolic expanders yields a new cosystolicexpander, assuming one of the complexes in the product, is not only cosystolicexpander, but rather a collective cosystolic expander.  We then show that the well known bounded degree cosystolic expanders, theRamanujan complexes are, in fact, collective cosystolic expanders. This enablesus to construct new bounded degree cosystolic expanders, by tensoring ofRamanujan complexes.  Using our new constructed bounded degree cosystolic expanders we construct{\em explicit} quantum LDPC codes of distance $\sqrt{n} \log^k n$ for any $k$,improving a recent result of Evra et. al. \cite{EKZ}, and setting a new recordfor distance of explicit quantum LDPC codes.  The work of \cite{EKZ} took advantage of the high dimensional expansionnotion known as cosystolic expansion, that occurs in Ramanujan complexes. Ourimprovement is achieved by considering tensor product of Ramanujan complexes,and using their newly derived property, the collective cosystolic expansion.

New Cosystolic Expanders from Tensors Imply Explicit Quantum LDPC Codes with $\Omega(\sqrt{n}\log^kn)$ Distance