Is Warp Drive Phys­i­cal­ly Pos­si­ble?

• Re­port rights in­fringe­ment
• pub­lished: 20 Jul 2013
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The physics of space­time de­scribed by Ein­stein's The­o­ry of Gen­er­al Rel­a­tiv­i­ty al­lows space­time to be­come warped due to the re­la­tion­ship be­tween mat­ter/en­er­gy den­si­ty and the grav­i­ta­tion­al field de­scribed by the Ein­stein Field Equa­tions, in the most gen­er­al form Ruv - (guvR)/2 + guv = (8pG/c4)Tuv, which equates that mat­ter and en­er­gy found in the large scale struc­ture of the uni­verse cre­ates a pos­i­tive tor­sion in space­time, caus­ing the warp­ing of space­time which is as­so­ci­at­ed with the strength of the grav­i­ta­tion­al force. In quan­tum me­chan­ics, zero point en­er­gy fluc­tu­a­tions can cre­ate neg­a­tive en­er­gy den­si­ty which should the­o­ret­i­cal­ly, in a large enough den­si­ty, cre­ate a neg­a­tive tor­sion on space­time in gen­er­al rel­a­tiv­i­ty. The con­se­quences of these the­o­ries, when com­bined, could change our com­mon sense no­tions of mo­tion and pro­vide a way to chal­lenge the cos­mic speed limit, the speed of light. In 1994, Miguel Al­cu­bierre de­vel­oped a geodesic equa­tion to de­scribe space-time warped in a bub­ble around a ship, cre­at­ing a "warp drive". The warp drive pro­posed by Al­cu­bierre could achieve near light speeds and even faster-than-light speeds by dis­tort­ing space-time. To ac­com­plish this, a the­o­ret­i­cal de­vice would gen­er­ate a field of neg­a­tive en­er­gy that would squeeze or stretch space-time, cre­at­ing the bub­ble. The bub­ble would ride the dis­tor­tions like a surfer on a wave. As ev­i­denced by the uni­for­mi­ty of the Cos­mic Mi­crowave Back­ground from the Big Bang, which is ex­plained by in­fla­tion­ary cos­mol­o­gy, space-time can ex­pand so quick­ly that ob­jects can move faster than the speed of light. There­fore the cur­rent mod­els of physics gen­er­al­ly allow for the ex­is­tence of a warp field that can ac­cel­er­ate ob­jects faster than the speed of light. The real ques­tions to ask is whether or not such a warp field can exist on macro­scop­ic scales and if so can it re­main sta­ble for long enough to ob­serve its ef­fects, on light in a laser in­ter­fer­om­e­ter for ex­am­ple. More­over it is un­known how it is tech­no­log­i­cal­ly pos­si­ble, i.e under what con­di­tions does mat­ter allow for the cre­ation of a neg­a­tive en­er­gy den­si­ty? In 1948, The­o­ret­i­cal Physi­cists Hen­drik Casimir and Dirk Pold­er pro­posed that a neg­a­tive press­sure can exist due to quan­tum vac­u­um fluc­tu­a­tions op­er­at­ing on very small scales in space and time and that if two un­charged metal­lic plates in a vac­u­um, placed a few mi­crom­e­ters apart the quan­tum fluc­tu­a­tions should cre­ate a force be­tween the 2 plates due to a dif­fer­en­tial vac­u­um en­er­gy den­si­ty be­tween the in­side and out­side of the plates. In a clas­si­cal de­scrip­tion, the lack of an ex­ter­nal field au­to­mat­i­cal­ly means that there is no field be­tween the plates, and no force would be mea­sured be­tween them. How­ev­er when the ze­ro-point field is in­stead stud­ied using the QED vac­u­um of quan­tum elec­tro­dy­nam­ics, it is seen that the plates do af­fect the vir­tu­al pho­tons which con­sti­tute the field, and gen­er­ate a net force. The force can give ei­ther an at­trac­tion or a re­pul­sion de­pend­ing on the spe­cif­ic ar­range­ment of the two plates. Al­though the Casimir ef­fect can be ex­pressed in terms of vir­tu­al par­ti­cles in­ter­act­ing with the ob­jects, it is best de­scribed and more eas­i­ly cal­cu­lat­ed in terms of the ze­ro-point en­er­gy of a quan­tized field in the in­ter­ven­ing space be­tween the ob­jects. It was not until 1997, how­ev­er, that a di­rect ex­per­i­ment, by Steve Lam­ore­aux, de­scribed above, quan­ti­ta­tive­ly mea­sured the force (to with­in 15% of the value pre­dict­ed by the the­o­ry) Pre­vi­ous work in the 1970's had ob­served the force qual­i­ta­tive­ly, and in­di­rect val­i­da­tion of the pre­dict­ed Casimir en­er­gy had been made by mea­sur­ing the thick­ness of liq­uid he­li­um films by Sabisky and An­der­son in 1972. Sub­se­quent ex­per­i­ments with liq­uid He­li­um-3 ap­proach an ac­cu­ra­cy of a few per­cent. Using Bose-Ein­stein Con­den­sates it may also be pos­si­ble to sup­press back­ground ef­fects oc­cur­ring be­tween in­di­vid­u­al molecules, such as the Van Der Waals Forces, which will help to quan­ti­fy the nec­es­sary bound­ary con­di­tions in the sec­ond quan­ti­sa­tion cal­cu­la­tions of Quan­tum Elec­tro­dy­nam­ics. This would allow the ef­fect of the vac­u­um to be­come dom­i­nant in the medi­um and allow for a more di­rect ob­ser­va­tion of neg­a­tive en­er­gy den­si­ty af­fect­ing it. This could also allow for fur­ther stud­ies in solid state physics on how the Casimir ef­fect could be con­trolled at the nanoscale and what physics and ap­pli­ca­tions can be gained from it. Some of this re­search, al­though ab­stract, may help us to un­der­stand how elec­tron­ic tran­si­tions occur at the small­est of scales and how to sup­press noise, such as that caused by the Casimir ef­fect, in nanoscale cir­cuit­ry, such as in the emer­gent fields of quan­tum cir­cuit­ry. There­fore by prob­ing some deep ques­tions of physics, and ex­am­in­ing the­o­ries such as "Warp Drives" we may un­cov­er a great deal of knowl­edge and gain pro­pos­als for some in­ter­est­ing ex­per­i­ments, per­haps even stum­bling upon the foun­da­tions of warp drive it­self along the way.