Possible Measurement of Quintessence and Density Parameter Using Strong Gravitational Lensing Events

We propose a possible method of measurement of the time variability of the vacuum energy using strong gravitational lensing events. As an example we take an Einstein cross lens HST 14176+5226 and demonstrate that the measurement of the velocity dispersion with an accuracy of ± 5 km/sec may allow for the determination of the time dependence of the vacuum energy as well as the density parameter with an accuracy of order 0.1 if the lens model is fixed.