In this paper we investigate the time-machine problem in the electromagnetic field. Based on a metric which is a more general form of Ori＇s, we solve the Einstein＇s equations with the energy-momentum tensors for ele...In this paper we investigate the time-machine problem in the electromagnetic field. Based on a metric which is a more general form of Ori＇s, we solve the Einstein＇s equations with the energy-momentum tensors for electromagnetic field, and construct the time-machine solutions, which solve the time machine problem in electromagnetic field.展开更多
This letter investigates the time-machine problem in perfect fluid cosmologies. It solves the Einstein’s field equations with the energy-momentum tensors for perfect fluid and constructs a class of time-machine solut...This letter investigates the time-machine problem in perfect fluid cosmologies. It solves the Einstein’s field equations with the energy-momentum tensors for perfect fluid and constructs a class of time-machine solutions, by which the time-machine problem in the perfect fluid cosmologies is solved.展开更多
基金Supported by the Start-up Fund of Fuzhou University under Grant No.0460022346
文摘In this paper we investigate the time-machine problem in the electromagnetic field. Based on a metric which is a more general form of Ori＇s, we solve the Einstein＇s equations with the energy-momentum tensors for electromagnetic field, and construct the time-machine solutions, which solve the time machine problem in electromagnetic field.
文摘This letter investigates the time-machine problem in perfect fluid cosmologies. It solves the Einstein’s field equations with the energy-momentum tensors for perfect fluid and constructs a class of time-machine solutions, by which the time-machine problem in the perfect fluid cosmologies is solved.
