Back to Publications List       Conservative quantum computing M. Ozawa Physical Rewiew Letters 89 (5): art. no. 057902 July 29 2002 Abstract The Wigner-Araki-Yanase theorem shows that conservation laws limit the accuracy of measurement. Here, we generalize the argument to show that conservation laws limit the accuracy of quantum logic operations. A rigorous lower bound is obtained of the error probability of any physical realization of the controlled-NOT gate under the constraint that the computational basis is represented by a component of spin, and that physical implementations obey the angular momentum conservation law. The lower bound is shown to be inversely proportional to the number of ancilla qubits or the strength of the external control field.         Home | About the Program | Our Research | Publications | People Related MURIs | Contact © Massachusetts Institute of Technology