¹q¸£¼ÒÀÀ¡G»P®É¶¡¦³ÃöªºÁ§¤B®æ¤èµ{¦¡ ¡Ð ªi¥]
°Ñ¦Ò¨Ó·½¡G¥»¸`¨ú§÷¦Û Gould and Tobochnik ¤§ An Introduction to Computer Simulation Methods ¤@®Ñ¡A
µ{¦¡«h¥Ñ§õ¦Ñ®v¬ã¨s¸s±qì¨ÓTrue BASC »y¨¥§ï¼g¬° Fortran / PGPLOT ª©¥»
®ÉÅÜ©ÊÁ§¤B®æ¤èµ{¡]ªi¥]´²®g¡^
®ÉÅܩʪºÁ§¤B®æ¤èµ{¦¡¤ñ«D®ÉÅܪº§xÃø±o¦h¡A±qªì©l®É¨è t = t0 ¶}©l¡A¨C±À¶i¤@¬q·L¤pªº®É¶¡¡A´Nn¸Ñ¥X¾ã®Mªi¨ç¼Æ¦bªÅ¶¡¤¤ªº¤À§G¡A§ó³Â·Ðªº¬O¡A³o¼Ëªº¦hÅܼƪº¸Ñ·L¤è°ÝÃD®e©ö³y¦¨¤£Ã©w¡A®Ú¥»¤W¯}Ãa¤F¸Ñªº¥¿½T©Ê¡C§Ú̦b³o¤p¸`¦]¦¹n¾Ç²ß«Ü«O¦u«Üéwªº¤èªk¡A¥H«K³B²z«D®ÉÅÜ©ÊÁ§¤B®æ¤èµ{¦¡ªº¿n¤À¨D¸Ñ°ÝÃD¡C ¡]¹³¬O°Ñ¦Ò®Ñ´£¨ì§Ṳ́£À³±Ä¥Î (18.17) ¦¡¨ººØ¤è¦¡ªººtºâªk¡A¦ÓÀ³±Ä¥Î (18.18) ¨º¼Ëªº¡A²Ó¸`½Ð¨£ì¤å¡^
Gould and Tobochnik ®Ñ¤¤±Ä¥Î¤F¥t¤@ºØ¤èªk¡A¥¦¬O§â®ÉÅܩʪi¨ç¼Æ¡]¤@©w¦³¹ê³¡»Pµê³¡¡^ªº¹ê³¡»Pµê³¡¤À¶}³B²z¡A±q쥻ªºÁ§¤B®æ¤èµ{¦¡¡]¥H¤U²¤Æ¬°¤@ºû¡^
i
hd/dt Ψ(x,t) = -h2/(2m) d2/dx2 Ψ(x,t) + V(x) Ψ(x,t)¦A¥O
Ψ(x,t) = R(x,t) + i I(x,t)
©î¶}¦¨¨â²Õ¤À§O³B²z
d/dt R(x,t) = Hop I(x,t)
d/dt I(x,t) = - Hop R(x,t)
¦pªG¦b³oùبϥΥb¨Bªk¡]¤¤ÂIªk¡^¡A³oºØºtºâªk¥»¨Ó¬On¦A¦hºâ¤¤ÂI±×²v²q´úȪº¡]×¹L¼ÆȤèªkªº¦P¾Ç¥i¦¸¦^·Q¤@¤U¶¥¶©¥¨®w¶ðªkªºµ¦²¤¡^¡A¦ý¦b³oùتºª¬ªp¦¨¤F I(x,t) ¬O R(x,t) ªº±×²v¡B-R(x,t) ¤]¬O I(x,t) ªº±×²v¡A´N¥i¥H¦w±Æ¦¨ R(x,t) ¥Ã»·¦b®æ¤lÂI¨DÈ¡A¦Ó I(x,t) ¥Ã»·¦b¤¤¶¡ÂI¨DÈ¡A¦p¦¹´N³£¤£¥²¦hªáÃB¥~ªº¤@¿ºâ¨D¤¤ÂI±×²v¤F¡A¨ãªºªººtºâªk¦p¤U¡G
R( x, t + Δt ) = R( x, t ) + Hop I( x,t + Δt/2 ) Δt
I( x, t + (3/2)Δt ) = I( x, t + Δt/2 ) - Hop R( x, t + Δt ) Δt
¦b³oºØ¤è¦¡ªºªí¥Ü¤U¡A¾÷²v±K«× P(x,t) = R(x,t)2 +I(x,t)2 ¤´¥i¥H¥Î¥H¤U³oºØ¤è¦¡¨Óªí¹F
P(x,t) = R(x,t)2 + I(x,t- Δt/2) I(x,t+Δt/2)
P(x,t+Δt/2) = R(x,t+Δt) R(x,t) + I(x,t+Δt/2)2
Visscher ÃÒ©ú¤Wzºtºâªk¦bº¡¨¬ -2
h/Δt < V < 2h/Δt - 2h2/(mΔx)2 ³o¼Ëªº V »P Δx ȬOéwªº [Ref. Computers in Physics 5(6), 596 (1991)]¡C
®Ö¤ßºtºâªk´£n¡G
¦ì¶Õªº§Î¦¡¬O¥H©w¸q¨ç¦¡ªº¤èªk¬°¤§¡C
¸Ñ·L¤À¤èµ{¤@©w»Ýnªì©lÈ¡Aªì©lªºªi¥]¦b¦¹±Ä¥Î·|µ¹¥X±`ºA¤À§G¤§¾÷²v±K«×ªÌ¡C¨äªì³t¡Bªi¥]¤j¤p¡]¼e«×¡^³£¥i¥Hª½±µ¦b°Ñ¼Æ¤¤½Õ¾ã¡C
¦b¦¹ªì©lȬO¤@ÓªiªºªÅ¶¡¤À§G¡A±Ä¥Î°ª´µ¡]§Y±`ºA¤À§G¡^¨ç¼Æ¡Aª`·Nªi¼Æ¡]¤S¥sªi¦V¶q¡^¤]¥[¶i¥h¼vÅT¨ä¬Û¦ì¡C¹ê³¡»Pµê³¡³£»Ýnªì©lÈ¡A¥¦Ì¦U¦Û¦b°ª´µ¤À§G¤W¦³®M¤W cos ªi¤Î sin ªi¡Aªiªº¸s³t«×±q¨ºùؤޤJ¡C¥»¸`©Ò±Ä¥Îªººtºâªk¡Aµê³¡»P¹ê³¡®t 1/2 Δt¡A¦]¦¹¥¦Ìªºªì©lȤ]¦b¤£¦Pªº®É¨è©w¸q¬Gµê³¡´N¤S¦h¤@Ó¬Û¦ì¡]¸Ô¨£°Ñ¦Ò®ÑÄy©Î½d¨Òµ{¦¡¡^¡Cȱoª`·Nªº¤@ÂI¬O¡A¦Ó¨ä¾÷²v¤À§G¬Ý¤£¨ì°Ê¶qªºª«½èªiªiªøµ²ºc¡A«ê¦n¥u§e²{¥ú·Æªº°ª´µ¤À§G¡C
½Ðª`·N³o»q¦³®É¶¡¡BªÅ¶¡¨âÓÅܼơA³£¦³³QÂ÷´²¤Æ¡A¦ý¦b¦¹¥u¦³®É¶¡¬O»Ýn°µ·L¨B±À¶i Δt ªº¡AHamiltonian ºâ²Å¤¤¥]§t¤F¹ïªÅ¶¡ªº¤G¦¸·L¤À¡A¦b¨ºùج۾FªñªºªÅ¶¡®y¼Ð®æ¤l¶¡ªº¡]ªi¡^¨ç¼ÆȬO¦³¤@°_§@¨Ç¹Bºâ¡A¦ý¤£¦PªÅ¶¡ªºªi¨ç¼Æ¤£¬O±q¡A¦Ó¬O¤@¶}©l´Nµ¹¤F¤À§G¦b¾ãӪŶ¡¡]§YªÅ¶¡¤¤³B³B¦³©w¸q¡^ªºªi¨ç¼Æ§@¬°ªì©l±ø¥ó¡C±qºtºâªk¤W¨Ó¬Ý¡Ax ÂI¤Wªºªi¨ç¼Æȥû·¬O¥Ñ¤W¤@®É¨è
¸Õ°Ý¡A·s®É¨è³B³Bªºªi¨ç¼Æ¤À§G¬O§_¤´º¡¨¬Á§¤B®æ¤èµ{¦¡¡A¤]´N¬O»¡
§Ú̬O¥ý§âªÅ¶¡
¼¶¼gµ{¦¡
µ¥¤£¤Î¤F¡H¥ý°½¬Ý¤@¤U§U±Ð»P¦Ñ®v¼gªº½d¨Òµ{¦¡
¦bµ{¦¡¤º´XÓ»Pª«²z¯S©Ê¦³Ãöªº°Ñ¼Æ
x0¡G°_©l¤¤¤ß¦ì¸m
k0¡Gªì©lªi¦V¶q¡]¥¿¤ñ©ó°Ê¶q¡A¤]´N¬O¥¿¤ñ©ó³t«×¡^
width¡Gªì©l °ª´µ¨ç¼Æ¡]±`ºA¤À§G¡^ §Î¤§ªi¥]ªº¼e«×
dx¡GÂ÷´²¤Æ«áªºªÅ¶¡¶¡¹j
dt¡GÂ÷´²¤Æ«áªº®É¶¡¶¡¹j
V0¡G¦ì¶Õ°ª«×
a¡G¦ì¤«ªº¥b¼e¡A¦ý¦b¶¥±èª¬®É¬O¦ì¾Àªº¦ì¸m
xmax¡Gx ¤è¦Vªº¥kÃä¬É
xmin¡Gx ¤è¦Vªº¥ªÃä¬É
¾Þ§@¡B°ÝÃD»P°Q½×
¤@¡B¥©Z¦ì¶Õ¤¤ªºªi¥]¶Ç¼½
§â¦ì¶Õ°ª«×©w¬°¹s¡C
¤G¡B®g¦V¶¥±èª¬ªº¦ì¶Õ
Æ[¹î³z®g¤Î¤Ï®g¡C
¤T¡B³z®g¦ìÂS
§ï³y¦ì¶Õ¨ç¼Æ¡A¨Ï¨ä¯à³B²z¦ìÂS¡]§Y¥©Z°Ï°ì¤¤¶¡¦³¤@°ª«×¦Û©wªº¬ð¥X¡^¡C
¥|¡B¦bµL²`¦ì¤«¤ºªººt¶i
¤¡B¨âÓªi¥]ªï±¹ï¼²¡]ªi¥]¹ï¼²¾÷¡^
½Ð¦Û¦æ¥[¤J¥t¤@Óªi¥]¡]¦bªi¥]ªì©l¤Æªº°Æµ{¦¡¤¤×§ï¡^¡AÆ[¹î¹ï¼²¡C
¦Û¤v¸Õ¸Õ¬Ýªi¥]¹ï¼²¡A¤£¦¨¥\¦A°Ñ¦Ò