Chris Monroe University of Maryland Department of Physics National Institute of Standards and Technology Putting Weirdness to Use atomsized transistors 2040 molecularsized transistors ID: 275334
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Slide1
Quantum Technology:
Chris
Monroe
University of MarylandDepartment of Physics
National Institute ofStandards and Technology
Putting Weirdness to UseSlide2
atom-sized
transistors
2040
molecular-sized
transistors
2025
Quantum mechanics
and computingSlide3
“When we get to the very, very small world – say circuits of seven atoms - we have a lot of new things that would happen that represent completely new opportunities for design.
Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics…”
“There's Plenty of Room
at the Bottom” (1959)
Richard FeynmanSlide4
Quantum
Mechanics
Information
Theory
Quantum Information Science
A new science for the 21
st
Century?
20
th
Century
21
st
CenturySlide5
Computer Science and Information Theory
Alan Turing (1912-1954)
universal computing machines
Claude Shannon (1916-2001)
quantify information: the bit
Charles Babbage (1791-1871)
mechanical difference engineSlide6
ENIAC
(1946)Slide7
The first solid-state transistor
(Bardeen, Brattain & Shockley, 1947)Slide8
Albert Einstein (1879-1955)
Erwin Schrödinger (1887-1961)
Werner Heisenberg (1901-1976)
Quantum Mechanics: A 20
th century revolution in physics
Why doesn’t the electron collapse onto the nucleus of an atom?Why are there thermodynamic anomalies in materials at low temperature?
Why is light emitted at discrete colors?
. . . .Slide9
The Golden Rules
of Quantum Mechanics
Rule #2:
Rule #1 holds as long as you don’t look!
|0 and
|1
Rule #1
:
Quantum
objects are waves and can
be
in states of superposition
.
“
qubit”:
|0
and
|1
|1
|0
or
p
robability
p 1-pSlide10
GOOD NEWS…
quantum parallel processing on 2N
inputs
Example: N=3 qubits
=
a
0
|000
+
a
1
|001
+
a
2
|010
+
a
3
|011
a
4
|100
+
a
5
|101
+
a
6
|110
+
a
7
|111
f(x)
…BAD NEWS…
Measurement gives random result
e.g.,
|101
f(x)
N=300 qubits: more information
than particles in the universe!Slide11
depends on
all
inputs
…GOOD NEWS!
quantum interferenceSlide12
|0 |0 + |1
|1 |1 -
|0
quantumNOT gate:
e.g
., |0 + |1
|
0
|0
|0
+
|1
|1
superposition
entanglement
(
)
…GOOD NEWS!
quantum interference
depends on
all
inputs
quantum
logic gates
|0 |0 |0 |0
|0 |1 |0 |1
|1 |0 |1 |1
|1 |1 |1 |0
quantum
XOR gate:Slide13
Quantum State:
[0]
[0] &
[1][1]
John Bell (1964)
Any possible “completion” to quantum mechanics will violate local realism just the sameSlide14
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
H
H
1
1Slide15
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
T
T
0
0
1
1Slide16
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
T
T
0
0
1
1
0
0Slide17
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
H
H
0
0
1
1
0
0
1
1Slide18
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
H
H
0
0
1
1
0
0
1
1
1
1Slide19
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
H
H
0
0
1
1
0
0
1
1
1
1
1
1Slide20
Entanglement: Quantum Coins
Two coins in aquantum superposition
[H][H]
& [T][T]
T
T
0
0
1
1
0
0
1
1
1
1
1
1
0
0
.
.
.
.
.
.Slide21
Application: quantum cryptographic key distribution
+
plaintext
KEY
ciphertext
ciphertext
KEY
plaintext
+Slide22
Quantum Superposition
From Taking the Quantum Leap
, by Fred Alan WolfSlide23
Quantum Superposition
From Taking the Quantum Leap
, by Fred Alan WolfSlide24
Quantum Superposition
From Taking the Quantum Leap
, by Fred Alan WolfSlide25
Quantum Entanglement
“Spooky action-at-a-distance” (A. Einstein)
From Taking the Quantum Leap
, by Fred Alan WolfSlide26
Quantum Entanglement
“Spooky action-at-a-distance” (A. Einstein)
From Taking the Quantum Leap
, by Fred Alan WolfSlide27
Quantum Entanglement
“Spooky action-at-a-distance” (A. Einstein)
From Taking the Quantum Leap
, by Fred Alan WolfSlide28
Quantum Entanglement
“Spooky action-at-a-distance” (A. Einstein)
From Taking the Quantum Leap
, by Fred Alan WolfSlide29
David Deutsch
“When a quantum measurement is made, the universe bifucates!”
Many Universes Multiverse
Many WorldsSlide30Slide31
David Deutsch
(1985)
Peter Shor (1994)Lov Grover
(1996)
fast number factoring N = p
q
fast database search
Quantum
Computers
and Computing
Institute of
Computer Science
Russian Academy
of Science
ISSN 1607-9817
0
500
1000
1500
2000
2500
3000
# articles mentioning “Quantum Information”
or “Quantum Computing”
Nature
Science
Phys. Rev. Lett.
Phys. Rev.
2005
2000
1995
1990
2010Slide32
Quantum Factoring
A quantum computer can factor numbers
exponentially faster than classical computers
15 = 3
5
38647884621009387621432325631 =
?
?
Look for a
joint property
of all 2
N
inputs
e.g.: the periodicity of a function
P. Shor, SIAM J. Comput.
26
, 1474 (1997)
A. Ekert and R. Jozsa, Rev. Mod. Phys.
68
, 733 (1996)
application: cryptanalysis
(
N
~
10
200
)
p
= period
r
= period (
a
= parameter)
x
2
x
2
x
(Mod 15)
0
1 1
1 2 2
2
4 4
3 8 8
4 16 1
5
32 2
6
64
4
7 128 8
8 256 1
etc…Slide33
E
rror-correction
Shannon (1948)
Redundant encoding to protect against (rare) errors
better off whenever
p < 1/2
unprotected
protected
0/1
potential error: bit flip
p
(error
) =
p
0/1
1
/
0
000/111
000/111
potential error: bit flip
0
1
0/1
0
1 etc..
take majoritySlide34
Decoherence
|0
+
|1
P
0
C
C
*
P
1
r
=
|0
+
|1
/4
{
|00000
+
|10010
+
|01001
+
|10100
+ |01010
-
|11011
-
|00110
-
|11000
-
|11101
-
|00011
-
|11110
-
|01111
-
|10001
-
|01100
-
|10111
+
|00101
}
+ /4
{
|11111
+
|01101
+
|10110
+
|01011
+ |10101
-
|00100
-
|11001
-
|00111
-
|00010
-
|11100
-
|00001
-
|10000
-
|01110
-
|10011
-
|01000
+
|11010
}
5-qubit code
corrects
all
1-qubit errors
to first order
Quantum error-correction
Shor (1995)
Steane (1996)Slide35Slide36
Trapped Atomic Ions
Yb
+
crystal
~5
mm
C.M. &
D. J.
Wineland
,
Sci. Am.
,
64 (Aug
2008)
R.
Blatt
&
D. J.
Wineland
,
Nature
453
,
1008
(2008)Slide37
State |
N
S
N
S
Quantum bit inside an atom:
States of relative electron/nuclear spin
State |
S
N
N
SSlide38Slide39
“Perfect” quantum measurement of a single atom
state |
state |
# photons collected in 200
m
s
Probability
30
20
10
0
0
0.2
atom fluoresces 10
8
photons/sec
laser
laser
atom remains dark
30
20
10
0
0
1
# photons collected in 200
m
s
>99% detection efficiency!Slide40
Cirac and Zoller, Phys. Rev. Lett.
74
, 4091 (1995)
Trapped Ion Quantum Computer
Internal states of these ions entangledSlide41Slide42
AFM ground state order
222 events
Antiferromagnetic
Néel
order of N=10 spins
441 events out of 2600 = 17
%
Prob
of any state at random =2 x (1/2
10
) =
0.2%
219 events
All in state
All in state
2600
runs,
a
=1.12Slide43
a
(C.O.M.)
b
(stretch)
c
(Egyptian)
d
(stretch-2)
Mode competition –
example: axial modes, N = 4 ions
Fluorescence counts
Raman Detuning
d
R
(MHz)
-15
-10
-5
0
5
10
15
20
40
60
a
b
c
d
a
b
c
d
2a
c-a
b-a
2b,a+c
b+c
a+b
2a
c-a
b-a
2b,a+c
b+c
a+b
carrier
axial modes only
mode
amplitudes
cooling beam
(see K. Brown)Slide44
1 mmSlide45
GaTech
Res. Inst.
Al/Si/SiO2
Maryland/LPS
GaAs/AlGaAs
Sandia Nat’l Lab: Si/SiO
2
NIST-Boulder
Au/QuartzSlide46
optical fiber
trapped
ions
trapped
ions
Photonic Quantum Networking
Linking ideal quantum memory
(trapped ion)
with ideal quantum communication channel
(photon)Slide47
Single atom here
Single atom hereSlide48
unknown
qubit
uploaded to
atom #1| + |
qubit
transfered
to atom
#
2
|
&
|
Quantum teleportation
of a single atom
S.
Olmschenk
et al., Science 323, 486 (2009).Slide49
we need more
time..
and more qubits..Slide50
Large scale vision (10
3 – 106
atomic qubits)Slide51
1 layer of transistors, 9-12 layers of
connectors
Interconnect complexity determines circuit complexity
Efficient transport of bits in the computer is crucial
ibm.com
Classical Computer ArchitectureSlide52Slide53
Physics
ChemistryComputer ScienceElectrical Engineering
MathematicsInformation Theory
Quantum
Mechanics
Information
Theory
Quantum Information Science
A new science for the 21
st
Century?
20
th
Century
21
st
CenturySlide54
Quantum Computing Abyss
?
noise
reduction
new
technology
error
correction
efficient
algorithms
20
>1000
<100
>10
9
theoretical requirements
for “useful” QC
state-of-the-art
experiments
# quantum bits
# logic gatesSlide55Slide56
Quantum Information Hardware at
Other condensed-matter
single atomic impurities in glass
single phosphorus atoms in silicon
Semiconductors
quantum dots
2D electron gases
Superconductors
Cooper-pair boxes (charge
qubits
)
rf
-SQUIDS (flux
qubits
)
Individual atoms and photons
ion traps
atoms in optical lattices
cavity-QEDSlide57Slide58
ENIAC
(1946)
1947Slide59Slide60
We have always had a great deal of difficulty in understanding the world view that quantum mechanics represents…
…Okay, I still get nervous with it…
It has not yet become obvious to me that there is no real problem. I cannot define the real problem, therefore I suspect there’s no real problem, but I’m not sure there’s no real problem.
Richard Feynman (1982)Slide61
N=10
28
N=1Slide62
Postdocs
Susan Clark (Sandia)
Wes Campbell (UCLA)
Taeyoung
Choi
Chenglin
Cao
Brian
Neyenhuis
Phil Richerme
Grahame Vittorini
Collaborators
Luming
Duan
Howard Carmichael
Jim Freericks
Alexey Gorshkov
Grad Students
David Campos
Clay Crocker
Shantanu
Debnath
Caroline
Figgatt
Dave Hayes (Sydney)
David
Hucul
Volkan
Inlek
Rajibul
Islam (Harvard)
Aaron Lee
Kale Johnson
Simcha
Korenblit
Andrew Manning
Jonathan
Mizrahi
Crystal Senko
Jake Smith
Ken Wright
Undergrads
Daniel Brennan
Geoffrey Ji
Katie Hergenreder
ARO
J
OINT
Q
UANTUM
I
NSTITUTE
www.iontrap.umd.edu
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