?-'0a:DFb+ ?J"ce@G!$d N"#%#P0&(!$'*&;)+@7-J,.1%KQ!0/(#R-'2'$13/(41S,5/(4 !$/(%?UTW'768VX4 9/Y #%.!2(&:=/;#-<>#R='H?-!2(4&(?-@ADZ4 =%(!$4&;BC=%4[?E-1SDF/(4>4>&;41G:/('H4\16]4.--1^I:6+'H4?J!2P7?J--11KQK /;DFL4G/;M_`ON r_t fhj$g7k i llHin m oqpsr nRt m r nutwvyx m r nRt '2& i l im o j0k z x f p{r nut}| r nut~vy rj t l2n i g i m Energy V(x)
E Classically allowed region
position
Classically forbidden region
Turning point
-K2=%&(45_2d e&(J/(&!$&;@.#R'$/(41S/( !$?
a
O1 /(.I F&;4>\K2-'221 CG"7I7W*7RR z x f psr nut}| j0k vh i r nRt^ r t g K2i 414>&!$?+('2?-=+/(-'21IBC'2& r nRt -1/(4ZBC'H?J?-'0DFJ1%K : = H K 2 K \ 4 O / X ; / % 0 ! E / Z D 4 > < $ ! 1 F D ; & L ; / w 4 ; / F 4 m BC'2&;, r nut~v r nutO *¡-¢2£-¤¥ rC¦ t m 4>1 l m v § lH o©¨ r nut lHª ¡J¢H£J¤\¥ r¬ t l2n lHn lHn~« _
l i m v § l i oM¨ lS l2ª o©¨ r nut l i ª ¡-¢2£-¤¥ lHn i Hl n i lHn l2n lHn i « H l H l ª 2 l ª o § lHn ©o ¨ r nut lHn « ¨ l2n \¡-¢H£J¤\¥ v l lHi n oM¨ j lHlH n lHlHªn o©¨ r nut llHni ª f r nutF® lHlHªnw¯ i° ¡-¢H£J¤\¥ b7=%:/(J/(=/(-1K./(%4"!$R'0i P24&(4\:=?J/F%!2<²{J1S/('/;4.i _`³a:bc´+DZ49K24/ l lHi n oM¨ j lSl2 n lHlHªn oM¨ r nRt llHni ª f r nutF® lHlHªnZ¯ i o i r nRtO r nRt ° ¡-¢2£-¤¥ v i T 42T-´ i ¶· ¸ ·¹ l l2lHi n lHf ª r nRtF® lHlHlªnZ¯ ª i o i r nRtO r nRtwvº &(4\!$?u/;4>&;, J,.!2K2-1%!$&;@.#%!$&(/ j lHni lHn o r nRt lHni vº ¼ V½4/\Y e<'21¾: 6+4>&/;49-,5!2K2-1%!$i &;@5/(4&(,À¿%&;:/d r nRt l2l n ® l2l2ªnZ¯ v f j lHlH n lHlHªn T 42T-´ l l2ª lHn lH® ª l2nw¯ v f j lSl2 n r nRt lHn  l lHr lHª½ªÄÃ0Ã$lHl2n nut v f j lH a1S/(4>KH&;!$/(-1K/(49? !2:/4ÅS=%!$/(-'21K2-P24 ?-1 ® l2l2ªnw¯ v ?-1 ® Æ r nRt2¯ i '2& lHª v Æ lHn i r nRt Ç3491%'0Dy=%(4È/(49&;4(=?J/BC'2& lHªÄÃ$l2n -1{/;49&;4!$?u/;4>&;,É4>)7#%&(4\((J'H1s/;'KH4/ l i f r nRt §ÊÆ i o r nRtO r nRt~vy lHn i i r nRt « i j
r± t rUµ t r» t rÁ t r _ Ht r _2_ t r_j t r_ t r_¦ t
T 42T-´
l i v r nutÌË § Æ i f r nut0Í l2n i i r nRt « i Z/F/( F#R'2-1S/Dw4È,.!$²H4Î/;4"!$#%#&('*)+-,.!0/(-'21{/(%!$/ li lHn iMÏ DF <?-4!H6Z/(' §Ð Æ r nRt « i f i r nRt~vy i Â Æ r nut vh r nut i  r nut~v Ò Ñ Æ r nRt Óe(J1%K5/( F&;4(=?L/F-1S/('/(494>)+#&(4\((-'21sBC'H& r lHªÄÃ$l2nut K2-P24\ lHª v Æ lHn Æ Ã$ r nRt v r nRt
r_¬ t r_± t r_µt r_» t r_Á t r j Ht rj _ t
r j2j t  ª r nut~vyÔÉ r nutOlHn ¼ 49K2414>&!$?Ä('2?-=+/(-'21'$BÕ/(4._9`³a:bcq ´+/(7=%´'$B/(4ÈBC'H&(, rj t m r nRt~vy r nutO *¡J¢H£J¤\¥ Ï Ò Ö r nut *¡Ø×EÙ\£-¤¥Ú¤ DF4>&;4È4 <'H1%-e6+J:/('H-'2,1.49BC'H!2&(&~/;J/(&4e!$P0&;!2@.?J <6+'HJ1%/O@.O/'$!$BÄ1S/(/%T 4!2##&;'*)7-,.!0/;J'H1 l 9Ã$l2n -Z('0DF1 -DF1{/; ¼<4BC<'2!2?-(?J4È'0Ö DFDw-4È1KI%!*DPH!*42@ud da}B p.r nRtwvº /;4>1 i r nut~vº i F:#¾!0/( !$i ?-?-@5NÌ-1%i 6+Ï 4#¾41%6+41H/\´-1 r nut~Û *¡ Ùؤ rj ¦ t m T 42T-´ ª r nRtwvºÜn rj ¬ t 4>1
!$1%6 DF <KHJPH4
l2ª vh 2l n lHª i Æ r nRt v lHn vº
rj ± t rj µ t
li v f rj » t l2n i v i i rj Á t Ç34F,.!*@È/;S=¾ <'21¾<?-=%6+4Z/(%!$/Ì/(4F<'H1%6+J/(-'21 l "Ã0lHn vº ;!0/( :¿%46I'21?-@"DF41 psr nRt eb+49VÌ#ÝF&;'2Ǻ%!2VSÞßJ?-JN~/O@{àÌe6+4>á1¾ÞÎ:JaO/Oâ@.ãäBC=#¾1%'2</(/(-4>'21S1 /;-!2 ?T i i ¼ r Ht å r nutæv ç m r nRt>ç i r _ t inut r Ï 44DFiÖJ/(/(4<? !2;: <>!2?Ä&(4\:=?J/;d r nRt F#&;'$N I 4 2 ! ¾ 0 ' H P 4 % # ( & H ' % $ ! ? L O / { @ 6 > 4 % 1 ( L O / @ $ ! H K ( & #R-1 '2&(!/(-&'2!$1%1!2KH?%4 /;'"lHn /(% 4ÎFJPH174>PH?-'74>&<>:L/O4@5?J@.'2#B½&;/('2#R4'2#%&(/(!2-&:'2/;1¾-<>!$?J?R4/(!$'51%J6s/;F/(PH44>?-'7#<>&;'2L/O%@{!2J1[J?-/(J/O@49'2-BÄ1S/(¿%41%&(6+P0!$-1? K5l2n!IT #¾!$&(/( <?-4
Oè.@85(JI,5-?-!2\&I!$2&;K2=%C©,"41Sé}/%´X*JêÌ/IÕ 947!HW:@Q07/('Q¾(¾ '0Dä/(%!$/I-13/;4[<>?-!H(( <>!$?-?-@NBC'2&; 66+41 Z ë &;4>K2-'21
rm nRt Ò ì r nRt 2í×Ìî £J¤\¥Ú¤+ï ì r nRtEvñð j$k z psr nut f xÈ| r j t
Z(5/I5/;4{¾#RÕ'2-1S7/;2"òÏ DFR%4>&;óX4 ¾Ö 0x ô3õÕ% nRtvÉ ´ :#R4<>-!2?E/(&;4!$/(,5g 4>i 1S/I "&;4ÅS=-&;468¾4\<>!2=%:4 !Gr ?-nuL/(t /(?-4QI(JJ1/[KH,5=? '2!$&;&\4 TA/(4\<4s1D <>!*!2@Q?´Ff '$Bps=¾/{r !$/(1%%6+4A?--1%K!2(/( <%4[-6(4'2!©?-=+/(.-'2/;1©%!01/{4\!$DZ&94A/;%4s!*PH/;4A=&;!M1J1%('2KQ?-=+#R/('2-'2-1H1W//(-' /(-1H%/;4[4>&;?-#¾4Bö'H/s?-!$!$/(1¾4\6©~R/(4'3/ODZ/(%4>441s&;/(-K2%S4>/, '2T Ba1{/('24/(/;=4&w&(1%DZJ1'2K8&6#R´H'2--1s1H/\/;´~!$4È1¾PS6M <'2-11%J4[/
[email protected]'$4B½46/;54Î!Q/(=BC'2&;&;1,I-1=K? !#R'2/;-%1S!0// ´ '21%4È!2##&;'*)+J,.!0/;4 Ò j0k z x f psr nut}|2Ã r2 t g i ?-4!26%7Z@8/('!/(:/(&4È!$BC-'HK2?JS?-'0/"DF?-J-114{K.'0<P2'24>1%&"14!</((-,.'21[!$?-BC?E'2-&;1H,I/;4>=&;? P0!2!$?wd !21%6G:'H?JPH4È/;4{a:b+cß4>)!2<Ø/;?J@HT%- ¦
(1)
(2)
E
x=a
Õ-K2=&;4 j dE÷Ì'2/(4>1S/;-!2?R414>&;K2@.#%&('2¿%?J4È=%(46[/;'564;<&;JR4È/(4"<>'211%4<Ø/;J'H1{BC'H&(,=? !2T r _ t ëZ!2&(&;-4>&Z/('/(%49&(-K2S/ j <'S9:Ô]ø r nutOlHn fúù ° û í ì _ í ×7þ ý î £-¤¥Ú¤ t r $ ¦ í ü ¦ Ñ ¤ _ (J1 :Ô]ø r nutOlHn fúù ° û í ì _ *×7þ ý î £J¤\¥Ú¤ rH¬ t ¦ íü Ñ ¤ r j t ëZ!2&(&;-4>&Z/('/(%49?J4>Bö/ j <'S § Ô ¤ r nRt:l2n f ù û í ì _ í × ý î £J¤\¥Ú¤ r2± t ¦ « í\ü Ñ _ ÿ ¤ rSµ t f Ñ :-1 § Ô ÿ r nRt:l2n f ù¦ « ûí\ü í ì _ × ý î £J¤\¥Ú¤ /(-1 -'21¾!e&;4>-1Q4"KHJ<'H!s'H1[1&;4>!01KH/e4\J<Ø'H(/('21A-,5'2!0149/ÈBC6+:'H'H &(O,,/!$4=1%?-6+!H<>4O//(4>!$'1%1%!2/(<>49?-4949/(?-'[=%4Bö/(/\T/('.4'H&(-+K2/;S!2/J1'$B &;4>/(? %!04"/(-/('2=%1¾&(:1--1#K[¾#¾4>'H/ODwJ1S4/È4>1DFL/(/;4/(:'H'S?J=+:4 N ÕS
(Õ5ÝÎ3È1%H 4½ '2M B/(2%24S+uò\,5ò R'SMO/.¾-é~,ò #RÕ'2{&(/;H!2¾1SÕ/#7&;2'2ò%R?J4],5é}¾/;0'8ô3DFõÕ%-<È]ò\A/(24%<2'HõÕ114\ò<Ø/(Õ-'2A1]ò BC'2{&;,Iò=õÕ? ½!2 !¿%$#%KH=#¼ &(?J@4 ¾ 4/(?J¾'0D9!0/w´½'2!2B½1%!96#¾/;41454/;4>&;1!$4/(&(-KH'2@ 1.-'2ÈBÄ(!"=%#¾<A'2/(/;4>%1S!0/;-/!2?%/(%4!2&(/;&;=J4&(1%&TÕJ1K#R4e'2¾-1H!$/&;È&(-4>!$& &;4 w!0(/ n8'0DF v 15- 1.!$/(1¾6 4 n[v T ¬
x=b
E (1)
(2)
(3)
Õ-K2=&;4 dE=114?J-1K.#R'$/;4>1S/( !$?Ä%!2&(&;-4>&\T x=a
x=b
!$1¾6[¼ (b+'2=,5#4#R/('H&(!$4~1%/;(%,5!0L/Ì/(/(/(4\%6Ä4Z´%#¾(!$'&(/(/; %<!0?-4/Õ-!$1 &;4~&(4-K21%-<'2 16+4>r1S /Ìt BCDZ&;'24È,ßDF/(J%?-?½4Z%?-!*4BöPH/\4 TÌb+'2,54wDF-?-?+¾4Z&(4 %4</(4\6 rm nut v _ ¡ × þ ý Ù\£J¤\¥Ú¤ í ¡ Ñ v _ <>'H § Ô ¤ r nutOlHn f ù¦ « oM¨ _ (-1 § Ô ¤ r nRt:l2n f ù¦ « r2» t Ñ & w-1%<>?J=%6ø 46.BC'H&F<'217PH4>1-4>1%<>4eÑ '2B!$##%?J@7-1ø KI/;4È<'21%14</(-'21sBC'H&:N È 4 # % H ! : e 4 B 2 ! Ø < ; / 2 ' ,I=%?-!H>ad 1&;4>KHJ'H1 j t DZ49%!*P24 r ¼
±
_ >< 'H § Ô ¤ r nutOlHn fúù oΨ _ :-1 § Ô ¤ r nRt:l2n fhù ¦« Ñ ø ¦« Ñ ø r2Á t _ _ _ j Ñ ì 4>)7#© f Ô ¤ ø ì r nRt:l2n ° f ¨ Ñ ì 4>)7#© Ô ¤ ø ì r nutOlHn ° T 42T-´ rm nRtwv j_ _ ì 2í× ý þ î £J¤\¥Ú¤ f ¨ _ ì *× ý þ î £-¤¥Ú¤ r¦ Ht Ñ Ñ â'0Dh=%:-1K i Ôqø ì r nutOlHn v Ô ÿ ì r nRt:l2n o Ôqø ì r nutOlHn _t r ¦ ÿ ¤ ¤ v f Ô ¤ ì r nRt:l2n o r¦ j t ÿ Dw49<!$1 DF&(J/(4 m r nRt !H i rm nRt v j_ _ ì 0×7ý î £J¤¥Ú¤ í f ¨ _ ì í ×7ý î £J¤\¥Ú¤ r¦H t i _ Ñ _ ì 0×7ý î £J¤¥Ú¤ Ñ f ¨ _ ì í ×7ý î £J¤¥Ú¤ t v j Ñ ! 2í Ñ " ! # r 2 ¦ ¦ &;JKHH¼ /\´+eDwKH4È!$-KH1½4´7/ =%(J1%K"/(%4<>'2114\<Ø/;J'H1.BC'2&;,I=? !2~BC'2&w/(%4<!2(4DF4>&;4/;4%!$&;&(-4>&~/('/(4 m$ r nut v j_ H í% _ (J1 § Ô! ÿ r nRt:l2n fhù¦ « f ¨ j <>'H § Ô ÿ ! r nRt:l2n hf ù¦ « & ¤ ¤ Ñ Ñ r ¦S¬ t _ _ j v j Hí% (J1 r ªut f ¨ & <'S r ªÄt r ¦H± t Ñ_ _ ¡J¢ í Ñ¡-¢ v j %í f ¨ j f ¨ j' ¡-¢ o j' í ¡-¢ ° r¦7µ t Ñ_ _ v § f ¨ ¦ %í )( ¡J¢ f í ¡-¢ * f ¨ )( ¡J¢ o í ¡J¢+* « r¦H» t Ñ µ
v f ¨ Ñ v f ¨ Ñ 41%<4 -
¶·
§ ¦_ í% ( *¡-¢ f í ¡J¢ * o ( *¡-¢ o í ¡-¢ * « § *¡J¢® o ¦_ í% ¯ o í ¡-¢[® f ¦_ í% ¯ « , , BC'H&(D!$&6s#&;'2#¾!$KH!$/(-1K %!2<²7D!$&6s#&;'2#%!2KH!$/(-1K D!*P24 D!*P24
r¦HÁ t rU¬ Ht
·¸ ¹ -. 1%< r nRt~v f ¨ ® & o ¦_ 2í ¯ ¡Ø× ý Ù*£J¤¥Ú¤ í ¡/ m &;4B rU¬ _ t Ñ ¨ ® _ í í ¡ × Ù*£J¤¥Ú¤ í ¡/ u n w t v r fÑ f ¦ ¯ ý m. -e!*P7-1K.'2/;!$-14\6{/;4"4>)7#%&(4\((J'H1BC'2& .J1%< r nRt !$1%6 .&(4>B r nRt ´¾DZ4"!$&;491'0DúJ1A! ¼ #R'H(L/;J'H1{/;'s<>!$? <=%?-!$/(4/(4È/;&;!21%(, ;:-'21<'74"m 0s<-4>1S/F=%(J1%K m Û 2222 m -1% < r nRr nRt t 2222 i 1 jt U r ¬ 2 . 2 2 m r nRt 2 v 222 m-1% < r nRt 222 i t U r $ ¬ 2 . 2 m _ v (U o . í% * rU¬0¦ t i í i 1 Ûv 3 _ o . í i 4 i rU¬2¬ t !$/:BC/;'H4>&F17=%?-!2!0&(/;KHJ'H4 1['2B/;49%!2&(&;J4& 4ÅS=%X!2?-'ÈZ(/;=' ,5,5!2&( 5>4H´*BC'2& !Î%!$&;&(-4>&ÕDFJ/(I? !$&;K24Z!0/(/(4>17=%!$/(-'21½´$/(4w/(=1%14>?-J1%K#%&('H%!$-?-L/O@ í i í i vº í i × þ î £J¤\¥Ú¤ 1 v rU¬$± t (_ o . í * ¼ 49&(4 %4</(-'21 <'7"4 0s<>J41H/ i i Ï v 2222 m J.&(1%4>
v 2222 of .. íí 2222 i rU¬$» t 4"(=,É'2BX/(%49&(4 %4</(-'21 !$1%6[/(&!$1¾:,5 ((J'H1[<>'S40s<-4>1S/; v ( o _ . %í * o (( of .. %í%í ** i 1 o rU¬$Á t i i v _ o ( i fo i.. o í .7. *6 í i r± Ht i o . o .7. 6 í v i o i. o . í i r± _ t .76 i v _i i r± j t r±2 t  1 o hv _
9894>/"=%èÈR1õ'0ÕDä;<>:½'21%ò+( ò\6+S4> &/(%4.#&('H?-4>, '2B!#R'$/(41S/( !$? DZ4>?-? J18/(%4.Ç=<9ë³!$##%&('*)+JN ½ V ,.!0/;J'H1½d V=0
energy
E<0 position (1)
(2)
x=a
(3)
ÕJKH=&(4 ¦ Ìd ëZ'H=1%6 O/!0/;4#%&('H?J4, x=b
$P0! !$1¾165¼ (BC'2&(4'H/(&sT?xRÎ4<>/O> <>DZ'24>& 46+1./(J1%%/(K{4s%4e/;#%' ?-!$J,5&(ÅS/(=%J</ !2?-1S4sn[/(=DFv;, -?J ?U´ /;!$!21%4><65'H<&('2/;@H&´Ä6+4-/(1?J%-K,54/(LD/'Q!*nP2<>?-4>;v !HBC=(( 1% ´H<><DF!$/(-?E'24/(1Q&(44#R'24>/(&;1%@244´Õ/(²7&'H!0J;1/;<4>4-?J/(È? !0<-/;1S44./(1'%4>!2&;/(K2<²@4 &;4>K2-'21[DF4>&;4 p Wx T a1{/;-&(4K2-'21½´!H<><'H&;6J1K/('/;49Ç=<9ëº!$#%#&('*)+-,.!0/(-'21Xd _ ì í × ý î £J¤\¥Ú¤ r±$¦ t . r nut~v m Ñ Á
¼ 4"!$##%?J <>!$/(-'21'$BÕ/(4"<>'2114\<Ø/;J'H1{BC'H&(,=?-!IBC'2&F&;4>KHJ'H1 r j t K2-P24\ rm nRt~v j <'H § Ô ÿ ¤ r nRtOlHn fúù¦ « i Ñ DF4>&;4
Ô ¤ r nRt:l2n v Ôqø r nRt:l2n o Ô ¤ r nRtOlHn ÿ ÿ ø ø r nRt:l2n ø Ô R n : t 2 l n Ô r v ÿ ! f ¤ ª ! b7=%:/(J/(=/(-1K./(%4"!$R'0P24&(4\:=?J/FJ1S/;'5/(494>)7#%&(4\((J'H1sBC'H& m r nut Dw4ÈKH4/ i ¤ <>'H § Ô r nutOlHn fúù¦ « v <'HA @ f ª fhù¦B ÿ v <'H @ ª o ù¦ f B v :-1 @ ùj f ª f ù¦ Co B v :-D1 @ ù¦ f ª Co B v :-D1 @ ù¦ f ª B <'S Er t o <>'HF @ ù¦ f ª B (-1 rG t v :-1 Gr t <>'H @-ª f ù¦ B f <>'H Gr t :-1 @ ª f ù¦ B <4)+'H1#R1'24\1<Ø4/; 1SZ /(/;!$' ?-?J@ ! 4><>)7'21#R1'24\1% <Ø4>/1SZ/( /(!$' ?-?J@ ! 6+('24\?-<>=+!*/(@7-'2J1%1 K KH('2&('0?-=+DF/(--1'21K r !H<><>4>#+/!$?-4 t r 1'$/e!H<><4#+/;!2?-4 t X'54?J-,5J1%!$/(4È/;49#7@+: <>!2?J?-@s=1%!H6+,5-;(J?-49:'H?J=/(-'21½´+DZ49,I=%:/F%!*P24 v Ô ø r nRtOlHn v r Ij H f _ t ùj ÿ v ® H f j_ ¯ ù 'H& H v _9!$1%6 psr nRt~vy BC'2& J>WKn >L ´+Dw49¾!*P24 Ü r f +tæv ® _ f j_ ¯ v j_ ù _
r±H¬ t r±2± t r±Sµ t r±2» t r±2Á t r}µ Ht r}µ _ t r}µ j t r}µ0 t
r}µ*¦ t r}µ$¬ t r}µ0± t r}µ2µ t
f v j ù NM . v j O ù
f v j ù P i O ¦ v '21?-@{ÅS=%!2&:/;4>&DZ!*PH4> ?-#4>! 1K2/(%Z1446[/('5R4 ¿&(4/:K2/;4-'261[-1HJ1%/;:'5/(4\/(!264"<>'$?-BÕ!H%((!$ ?J<>Bö!$N}DZ?-?-@s!*PH!$4>?-?-?J4>'01DZK24/(6 % BC'2&F-1+¿%1J/(49¾!$&;&(-4>&
_2_
r}µ0» t r}µ0Á t r» Ht