image: This is a photograph of the device used (black square with gold wires leading to it) sitting on a sample board. In order to control and read out the state of the qubit, it was necessary to be able to deliver precise electrical signals in approximately one billionth of a second. This sample board is able to deliver these fast electrical signals to the sample’s edge. Connection from the board to the sample is done with many wire bonds (very thin gold wires). The black square is a piece of semiconductor roughly 4mm on a side. The device being tested is in the bottom-right corner of the piece, with most of the space used to provide room for the wire bottoms. The actual qubit is roughly one micron long, about 50 times smaller than the width of a human hair. This image relates to a paper that appeared in the April 13, 2012, issue of Science, published by AAAS. The paper, by M.D. Shulman at Harvard University in Cambridge, MA, and colleagues was titled, “Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits.” view more
Credit: Image © <i>Science</i>/AAAS