Low Noise Single Electron Source
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Low Noise Single Electron Source Jin Zhang , Yury Sherkunov, Nicholas d’Ambrumenil, Boris Muzykantskii University of Warwick, U.K. Conference on Computational Physics 2009, Kaohsiung, 16 th , Dec
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Low Noise Single Electron Source. Jin Zhang , Yury Sherkunov, Nicholas d’Ambrumenil, Boris Muzykantskii University of Warwick, U.K. Conference on Computational Physics 2009, Kaohsiung, 16 th , Dec. Single Electron Excitation. Arbitrary Pulse: . Single Electron Excitation. - PowerPoint PPT Presentation
Transcript of Low Noise Single Electron Source
Low NoiseSingle Electron Source
Jin Zhang , Yury Sherkunov, Nicholas d’Ambrumenil, Boris Muzykantskii
University of Warwick, U.K.
Conference on Computational Physics 2009, Kaohsiung, 16th, Dec.
)(tV
Single Electron Excitation
Arbitrary Pulse:
t
dttVt ')'()()(tie
FkFk
Single Electron Excitation
2 2
2( )V tt
Minimal Excitation States (MES):
( )i t t iet i
Ivanov Lee Levitov, Phys. Rev. B 56, 6839
Keeling Klich Levitov, Phys. Rev. Lett. 97, 116403
t
dttVt ')'()(
FkFk
Noise Characterization
D)D(12 pt
QPartition Noise:
Thermal Noise:
eqQ
thQ
ptQQ 2222
f2 DTtth
Q
Equilibrium Noise (T=0):
DD
)εDlog(t Ff2 eq
Q
fFtvL
0 t
D
ft
Noise Minimization
Minimized by setting
0
D
t
for abrupt opening at GHz
?0t
D
ft
D
Low temperature -- mKHigh frequency -- GHz
),1(2 DDpt
Q 1D
),εDlog(t Ff2 eq
Q
,DTt f2 th
Q
1
Suppression of the Equilibrium Noise1. Single Lorentzian pulse to the barrier
2. Double Lorentzian pulses to the barrier
11
11
11
11
22
22Im)(
ittitt
ittitttA
( ) Im t iA tt i
When 0.8 (0) 1A
2|)(|)( tAtD
212
eqQ
412
eqQ
1
1
1
21
21
t
Low Noise Single Electron SourceTotal noise from single electron emission:
JZ YS NdA BMPhys. Rev. B 80, 245308
Phys. Rev. B 80, 041313 (R)
Probability Distribution:
High yield singleelectron emission
Suppressed multipleelectron emission
20
20
0
)(2)(
tttV
10
Conclusion
• Suppressing the quantum equilibrium noise at low temperature by tuning the tunneling barrier (QPC) transparency
• Low noise on-demand single electron source at low temperature
Many thanks for your attention!
Single Electron SourceFève et.al, Science 316,1169
Averaged over millions of eventsToo Noisy
Working Condition: GHz, mK
Keeling et.al, PRL 101, 196404
Minimize the Noise?
Optimal Electronic EntanglerApply Single Lorentzian pulse to the barrier
( ) Im t iA tt i
212 Q
“useful”, 1Q 0QNot “useful”
No excessive not “useful” noise at all
50% Entanglement efficiency,Theoretical maximum
Theory ofFull Counting Statistics (I)
( ) i nn
n
P e
Characteristic Function
Current, Noise, etc...0
ln( )
mm
mQi
Understood with density matrix of outgoing states:
)'()',()()'()',()( tBttntBtAttntAbbn inR
inLRR
outR
R
Lti
ti
R
L
aa
S
tBetAetAtB
bb
)()()()(
)(
)(
Theory ofFull Counting Statistics (II)
Abanov et.al 20082 (1 )j j
j
Q n n
jn
jn
ji
jj nQenn ,)1()( 1,)1()( j
ijj nQenn
jj
iniQi neee j )1(1)(
Non Optimal PulsesFor finite cut-off, additional noises are induced
