This paper proposes a modification of the Alcubierre and Natario Warp Drive, that requires far less energy to produce the warp bubbles. To read a .PDF of the paper, click here.

"We compute the negative energy density requirements for a Warp Bubble with a radius of 100 meters(large enough to contain a ship) moving with a speed of 200 times light speed(fast enough to reach stars at 20 light-years away in months not in years) ... However both Alcubierre and Natario Warp Drives as members of the same family of the Einstein Field Equations requires the so-called Shape Functions in order to be mathematically defined. We present in this work two new Shape Functions one for the Alcubierre and another for the Natario Warp Drive Spacetimes that allows arbitrary Superluminal speeds while keeping the negative energy density at ”low” and ”affordable” levels. ... Alcubierre and Natario Warp Drive were regarded as unphysical by the scientific community due to the large negative energy density requirements demanded to create these Spacetimes.The argument of the scientific community is valid due to the factor c4/G from the Einstein Field Equations multiplied by the square of the Warp Drive speed vs when attaining superluminal velocities that demands large outputs of negative energy to maintain the Warp Drive while quantum theory only allow microscopical amounts of it and we know that we cannot violate quantum physics. So the Warp Factor allows ourselves to lower the negative energy density requirements without violations of quantum physics"

Fine, but in addition with superconducting meta-materials it may be possible to reduce c^4/G by a factor of 10^40 or more making the energy requirement for warp drive even smaller. What about time dilation back at Earth? - Jack Sarfatti