Quantum bits--called qubits--can perform mathematical operations that are intractable, by encoding both ones and zeroes simultaneously in what is called a superposition of values. However, to create full fledged quantum computers something like an acknowledgment pulse is needed, and MIT claims to have one. R.C.J.
Future versions of the Internet will store and transfer quantum information--qubits--from node to node, researchers predict. After each operation, an acknowledgement pulse signaling a successful transfer must be sent to insure the smooth interchange of information among network nodes. Acknowledgement entails inspecting the data values, but that would destroy quantum information. Therefore, MIT scientists have invented a new method of signaling the reception of qubits without revealing their values. The quantum memory value is received from polarized qubits on incoming photons with the herald pulse acknowledging its successful storage in the cold gas. Later, another photon with the same polarization state as the original is retrieved from the gas, thereby proving that the herald pulse preserved the quantum information by only announcing the successful reception and storage of the qubits without resolving their superposition of quantum values.