Science, 30 August 1996: "Enforcing Coherent Evolution in Dissipative Quantum Dynamics" Cirac, Pellizzari, Zoller [Precis] The major obstacle to the preparation and manipulation of many-particle entangled states is decoherence due to the coupling of the system to the environment. A scheme to correct for the effects of decoherence and enforce coherent evolution in the system dynamics is described and illustrated for the particular case of the ion-trap quantum computer. The preparation and manipulation of N-particle entangled states is fundamental to the investigation of basic aspects of quantum mechanics and is the basis of applications such as quantum computation, teleportation, cryptography. and spectroscopy. The error correction schemes proposed so far have focused on preserving a given entangled state (memory errors). We introduce a method to correct for the effects of decoherence in the dynamical proccss of preparation and modification of entangled states (gate errors). We illustrate our scheme in the context of the ion-trap QC. ----- This 4-page paper is packed with equations. We will scan to JPEG for those without access to Science. Send us a blank message with the subject: QDY_nam We have to enlarge the fine-print originals to make readable images, usually in the 150kb range. Does anyone know of a program to do text and equations for easy- reading, easy access to a Web site?