  In this article, we consider the possibility of manipulation of quantum
signals, ensured by the use of the tripod-type atomic memory cell. We show that
depending on a configuration of driving fields at the writing and reading, such
a cell allows both to store and transform the signal. It is possible to provide
the operation of the memory cell in a Mach-Zehnder interferometer mode passing
two successive pulses at the input. We proposed a procedure of partial signal
read out that provides entanglement between the retrieved light and the atomic
ensemble. Thus, we have shown that tripod atomic cell is a promising candidate
to implement of quantum logical operations, including two-qubit ones, that can
be performed on the basis of only one cell.

Quantum Physics