  By choosing H nucleus in Carbon-13 labelled trichloroethylene as one qubit
environment, and two C nuclei as a two-qubit system, we have simulated quantum
decoherence when the system lies in an entangled state using nuclear magnetic
resonance (NMR). Decoupling technique is used to trace over the environment
degrees of freedom. Experimental results show agreements with the theoretical
predictions. Our experiment scheme can be generalized to the case that
environment is composed of multiple qubits.
