SLIDE 1 A tale of quantum computers
Alexandru Gheorghiu gheorghiuandru@gmail.com
The University of Edinburgh
T H E U N I V E R S I T Y O F E D I N B U R G H
SLIDE 2
A long time ago in a galaxy not so far away...
SLIDE 3
Quantum Mechanics
SLIDE 4
Quantum Mechanics
1900s-1930s Inception of Quantum Mechanics
SLIDE 5
Quantum Mechanics
1900s-1930s Inception of Quantum Mechanics
SLIDE 6
Quantum Mechanics
1900s-1930s Inception of Quantum Mechanics Extremely successful theory leading to many many discoveries...
SLIDE 7
Quantum Computation
SLIDE 8
Quantum Computation
While highly accurate, quantum systems are extremely complex
SLIDE 9
Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
SLIDE 10 Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
- “What kind of computer are we
going to use to simulate physics?” Richard Feynman (1981)
SLIDE 11 Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
- “What kind of computer are we
going to use to simulate physics?” Richard Feynman (1981)
- Simulate physics = simulate QM
SLIDE 12 Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
- “What kind of computer are we
going to use to simulate physics?” Richard Feynman (1981)
- Simulate physics = simulate QM
- Exponential overhead for classical
computers
SLIDE 13 Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
- “What kind of computer are we
going to use to simulate physics?” Richard Feynman (1981)
- Simulate physics = simulate QM
- Exponential overhead for classical
computers
- A task for super-computers
SLIDE 14 Quantum Computation
While highly accurate, quantum systems are extremely complex Polarizations for system of 100 photons → 2100 variables!
- “What kind of computer are we
going to use to simulate physics?” Richard Feynman (1981)
- Simulate physics = simulate QM
- Exponential overhead for classical
computers
- A task for super-computers
Feynman’s idea: Make a computer with quantum computing elements!
SLIDE 15
Brief history
SLIDE 16 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
SLIDE 17 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
- 1990s Theory of efficient quantum simulation. Seth Lloyd
SLIDE 18 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
- 1990s Theory of efficient quantum simulation. Seth Lloyd
- 1994 Peter Shor’s algorithms for factoring and discrete log.
Quantum computers can break RSA, Diffie-Hellman, El Gamal, Elliptic Curve Cryptography and others
SLIDE 19 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
- 1990s Theory of efficient quantum simulation. Seth Lloyd
- 1994 Peter Shor’s algorithms for factoring and discrete log.
Quantum computers can break RSA, Diffie-Hellman, El Gamal, Elliptic Curve Cryptography and others
- 2001 Experiment factors 15 using Shor’s algorithm
SLIDE 20 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
- 1990s Theory of efficient quantum simulation. Seth Lloyd
- 1994 Peter Shor’s algorithms for factoring and discrete log.
Quantum computers can break RSA, Diffie-Hellman, El Gamal, Elliptic Curve Cryptography and others
- 2001 Experiment factors 15 using Shor’s algorithm
- 2010s D-Wave, Google, IBM, NQIT and various universities
work on developing quantum computers
SLIDE 21 Brief history
- 1980s Idea of quantum computation. Paul Benioff, Yuri
Manin, Richard Feynman, David Deutsch
- 1990s Theory of efficient quantum simulation. Seth Lloyd
- 1994 Peter Shor’s algorithms for factoring and discrete log.
Quantum computers can break RSA, Diffie-Hellman, El Gamal, Elliptic Curve Cryptography and others
- 2001 Experiment factors 15 using Shor’s algorithm
- 2010s D-Wave, Google, IBM, NQIT and various universities
work on developing quantum computers How serious is the involvement in quantum computation?
SLIDE 22
Who invests in Quantum Computing?
SLIDE 23
Development and current status
SLIDE 24
Other applications
SLIDE 25 Other applications
- Data mining and efficient unstructured querying
SLIDE 26 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
SLIDE 27 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
- Efficient distributed computation
SLIDE 28 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
- Efficient distributed computation
- Efficient communication
SLIDE 29 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
- Efficient distributed computation
- Efficient communication
- Data compression
SLIDE 30 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
- Efficient distributed computation
- Efficient communication
- Data compression
- Quantum cryptography (more on that later)
SLIDE 31 Other applications
- Data mining and efficient unstructured querying
- Machine learning and quantum machine learning
- Efficient distributed computation
- Efficient communication
- Data compression
- Quantum cryptography (more on that later)
“For me, the single most important application of a quantum computer is disproving the people who said it’s impossible. The rest is just icing on the cake” Scott Aaronson
SLIDE 32
Misconceptions
SLIDE 33
Misconceptions
SLIDE 34
How do they work?
SLIDE 35
How do they work?
SLIDE 36
How do they work?
SLIDE 37
How do they work?
SLIDE 38
How do they work?
Bits: 0, 1 Qubits: |0, |1
SLIDE 39
How do they work?
Bits: 0, 1 Qubits: |0, |1 General qubit: |ψ = α |0 + β |1
SLIDE 40
How do they work?
Bits: 0, 1 Qubits: |0, |1 General qubit: |ψ = α |0 + β |1 α, β are amplitudes (complex numbers)
SLIDE 41
How do they work?
Bits: 0, 1 Qubits: |0, |1 General qubit: |ψ = α |0 + β |1 α, β are amplitudes (complex numbers) |α|2 probability of observing |0, |β|2 probability of observing |1 |α|2 + |β|2 = 1
SLIDE 42
How to make them?
SLIDE 43 How to make them?
magnetic fields
SLIDE 44 How to make them?
magnetic fields
crystals
SLIDE 45 How to make them?
magnetic fields
crystals
- Photon paths + mirrors and
crystals
SLIDE 46 How to make them?
magnetic fields
crystals
- Photon paths + mirrors and
crystals
fields
SLIDE 47 How to make them?
magnetic fields
crystals
- Photon paths + mirrors and
crystals
fields
- Hybrid systems and others...
SLIDE 48
Summary
SLIDE 49 Summary
Classical
Quantum
SLIDE 50 Summary
process Classical
- Bits (0, 1)
- Logical (AND, OR,
NAND) Quantum
- Qubits (α |0 + β |1)
- Unitary
(interference)
SLIDE 51 Summary
process
Classical
- Bits (0, 1)
- Logical (AND, OR,
NAND)
intensity etc Quantum
- Qubits (α |0 + β |1)
- Unitary
(interference)
polarization etc
SLIDE 52
How will they look?
SLIDE 53
Challenges
SLIDE 54 Challenges
- Maintaining superposition
states (coherence)
SLIDE 55 Challenges
- Maintaining superposition
states (coherence)
environment → decoherence
SLIDE 56 Challenges
- Maintaining superposition
states (coherence)
environment → decoherence
SLIDE 57 Challenges
- Maintaining superposition
states (coherence)
environment → decoherence
SLIDE 58 Challenges
- Maintaining superposition
states (coherence)
environment → decoherence
- Noise
- Fault tolerance
- Scalability
SLIDE 59 Challenges
- Maintaining superposition
states (coherence)
environment → decoherence
- Noise
- Fault tolerance
- Scalability
- Only technological
limitations
SLIDE 60
State of the art
SLIDE 61 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
SLIDE 62 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
SLIDE 63 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
- 2012 Universal quantum computation on 2 fault tolerant
qubits
SLIDE 64 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
- 2012 Universal quantum computation on 2 fault tolerant
qubits
- 2014-2015 Qubits and gates in silicon chips
SLIDE 65 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
- 2012 Universal quantum computation on 2 fault tolerant
qubits
- 2014-2015 Qubits and gates in silicon chips
- 2015 D-Wave 2X, 1000 qubits, optimization problems, no
fault tolerance
SLIDE 66 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
- 2012 Universal quantum computation on 2 fault tolerant
qubits
- 2014-2015 Qubits and gates in silicon chips
- 2015 D-Wave 2X, 1000 qubits, optimization problems, no
fault tolerance
- 2020 NQIT, Q20:20, fault tolerant (20 qubits), scalable
SLIDE 67 State of the art
- 2001 Shor’s algorithm factors 15 on 7 qubits
- 2011 Shor’s algorithm factors 21
- 2012 Universal quantum computation on 2 fault tolerant
qubits
- 2014-2015 Qubits and gates in silicon chips
- 2015 D-Wave 2X, 1000 qubits, optimization problems, no
fault tolerance
- 2020 NQIT, Q20:20, fault tolerant (20 qubits), scalable
- And others...
SLIDE 68
Towards quantum secure cryptography
SLIDE 69
Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography?
SLIDE 70
Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography? Existing crypto based on unproven hard problems (factoring, discrete log etc)
SLIDE 71
Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography? Existing crypto based on unproven hard problems (factoring, discrete log etc) How long do you want your data to stay secure? (∼ 20 years)
SLIDE 72
Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography? Existing crypto based on unproven hard problems (factoring, discrete log etc) How long do you want your data to stay secure? (∼ 20 years) How long to make the Internet quantum secure? (∼ 20 years)
SLIDE 73
Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography? Existing crypto based on unproven hard problems (factoring, discrete log etc) How long do you want your data to stay secure? (∼ 20 years) How long to make the Internet quantum secure? (∼ 20 years) What about problems that are hard for quantum computers?
SLIDE 74 Towards quantum secure cryptography
Will quantum computers pose a threat to cryptography? Existing crypto based on unproven hard problems (factoring, discrete log etc) How long do you want your data to stay secure? (∼ 20 years) How long to make the Internet quantum secure? (∼ 20 years) What about problems that are hard for quantum computers? “Even if a classical protocol is proven secure based on the hardness
- f some problem, and that problem is hard even for quantum
computers, we have no guarantee that the protocol is secure against quantum computers.” Dominique Unruh
SLIDE 75
Quantum Cryptography
SLIDE 76 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
SLIDE 77 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
mechanics is correct, unconditional security
SLIDE 78 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
mechanics is correct, unconditional security
power cannot break the encryption
SLIDE 79 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
mechanics is correct, unconditional security
power cannot break the encryption
- First development: quantum
money scheme
SLIDE 80 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
mechanics is correct, unconditional security
power cannot break the encryption
- First development: quantum
money scheme
SLIDE 81 Quantum Cryptography
- Idea: do not base security
- n computational problems,
but on the laws of physics
mechanics is correct, unconditional security
power cannot break the encryption
- First development: quantum
money scheme
- Quantum key distribution
- Uses one-time pad
SLIDE 82
One-time pad
SLIDE 83
One-time pad
M1
SLIDE 84
One-time pad
M1 ⊕ Key
SLIDE 85
One-time pad
M1 ⊕ Key = C1
SLIDE 86
One-time pad
M1 ⊕ Key = C1 C1 ⊕ Key = M1
SLIDE 87
One-time pad
SLIDE 88
One-time pad
M2 ⊕ Key = C2
SLIDE 89
One-time pad
M2 ⊕ Key = C2 C1 ⊕ C2 = M1 ⊕ M2
SLIDE 90
Quantum Key Distribution (QKD)
SLIDE 91
Quantum Key Distribution (QKD)
Make two parties share a random secret key
SLIDE 92
Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages
SLIDE 93
Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages Communication bandwidth limited by key rate
SLIDE 94 Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages Communication bandwidth limited by key rate
SLIDE 95 Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages Communication bandwidth limited by key rate
principle
SLIDE 96 Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages Communication bandwidth limited by key rate
principle
SLIDE 97 Quantum Key Distribution (QKD)
Make two parties share a random secret key Arbitrary size key → arbitrary number of messages Communication bandwidth limited by key rate
principle
security (based
SLIDE 98
Quantum Key Distribution (QKD)
SLIDE 99
Quantum Key Distribution (QKD)
What about exploiting the implementation?
SLIDE 100
Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
SLIDE 101 Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
independence
SLIDE 102 Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
independence
untrusted devices
SLIDE 103 Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
independence
untrusted devices
entanglement
SLIDE 104 Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
independence
untrusted devices
entanglement
correlations
SLIDE 105 Quantum Key Distribution (QKD)
What about exploiting the implementation? Not a problem!
independence
untrusted devices
entanglement
correlations
realize
SLIDE 106
What you can buy today
SLIDE 107
What you can buy today
SLIDE 108
State of the art
SLIDE 109 State of the art
- QKD backbone
- To be completed 2016
- QuantumCTek
- Commercial and government
use
SLIDE 110 State of the art
- QKD backbone
- To be completed 2016
- QuantumCTek
- Commercial and government
use
- QKD network
- To be completed
- Battelle and ID Quantique
- Commercial and government
use
SLIDE 111
Other uses of Quantum Cryptography
SLIDE 112 Other uses of Quantum Cryptography
SLIDE 113 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
SLIDE 114 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
- Quantum money
SLIDE 115 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
- Quantum money
- Secure delegated (quantum) computation
SLIDE 116 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
- Quantum money
- Secure delegated (quantum) computation
- Secure multi-party (quantum) computation
SLIDE 117 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
- Quantum money
- Secure delegated (quantum) computation
- Secure multi-party (quantum) computation
- Relativistic quantum cryptography
SLIDE 118 Other uses of Quantum Cryptography
- Secure authentication
- Digital signatures
- Quantum money
- Secure delegated (quantum) computation
- Secure multi-party (quantum) computation
- Relativistic quantum cryptography
“In the next 6-24 months, organizations without a well articulated quantum risk management plan will loose business to organizations that do” Michele Mosca (October 2015)
SLIDE 119
Recommended reading
SLIDE 120
Recommended technical reading
SLIDE 121 Conclusions
- Quantum computers would be extremely useful
- They can solve problems efficiently using interference
- Recently, lots of investments and interest
- Poses a risk to existing cryptography
- Quantum cryptography to the rescue
- Unconditional security and device independence
- Commercial systems already exist
SLIDE 122 Conclusions
- Quantum computers would be extremely useful
- They can solve problems efficiently using interference
- Recently, lots of investments and interest
- Poses a risk to existing cryptography
- Quantum cryptography to the rescue
- Unconditional security and device independence
- Commercial systems already exist
There’s still a lot of work to be done...
SLIDE 123 Conclusions
- Quantum computers would be extremely useful
- They can solve problems efficiently using interference
- Recently, lots of investments and interest
- Poses a risk to existing cryptography
- Quantum cryptography to the rescue
- Unconditional security and device independence
- Commercial systems already exist
There’s still a lot of work to be done... “I don’t pretend we have all the answers. But the questions are certainly worth thinking about.” Arthur C. Clarke
SLIDE 124
Thank you!
SLIDE 125 Reading material and references
- Quantum Computing since Democritus -
http://www.scottaaronson.com/democritus/
- Quantum Computation and Quantum Information -
http://www.amazon.com/ Quantum-Computation-Information-Anniversary-Edition/ dp/1107002176
http://www.scottaaronson.com/blog/
http://michaelnielsen.org/blog/
- Nice paper on quantum crypto - http://www.nature.com/
nature/journal/v507/n7493/full/nature13132.html
- Quantum Computing for Computer Scientists -
http://www.amazon.co.uk/ Quantum-Computing-Computer-Scientists-Yanofsky/ dp/0521879965/ref=sr_1_1?ie=UTF8&qid=1451928677& sr=8-1&keywords=quantum+computing+for+computer+ scientists
SLIDE 126 References
- Feynman’s original paper on QC - https://www.cs.
berkeley.edu/~christos/classics/Feynman.pdf
- Efficient quantum simulation, Seth Lloyd - https://www.
sciencemag.org/content/273/5278/1073.abstract
- Experiment to factor 15 - http://www.nature.com/
nature/journal/v414/n6866/full/414883a.html
- Experiment to factor 21 - http://www.nature.com/
nphoton/journal/v6/n11/full/nphoton.2012.259.html
- Universal QC with 2 qubits - http://www.nature.com/
nature/journal/v484/n7392/abs/nature10900.html
- QC in silicon - http://www.nature.com/nature/journal/
v526/n7573/full/nature15263.html
- NQIT and Q20:20 - http://nqit.ox.ac.uk/technologies
- D-Wave - http://www.dwavesys.com/
SLIDE 127 References
- Source for Dominique Unruh’s quote on slide 19 -
https://eprint.iacr.org/2010/212.pdf
- Michele Mosca on the quantum risk to cryptography -
https://www.youtube.com/watch?v=eEn8LT119bY
- Review of quantum cryptography - http://journals.aps.
- rg/rmp/abstract/10.1103/RevModPhys.74.145
- Device independence - https:
//www.icfo.eu/images/publications/J07-045.pdf
- Quantum machine learning -
http://www.scottaaronson.com/papers/qml.pdf
- List of existing quantum algorithms -
http://math.nist.gov/quantum/zoo/
- Workshop on quantum computation - http:
//workshop.rosedu.org/2015/sesiuni/quantum-comp
SLIDE 128 References
- Image on slide 3 (Solvay conference) -
https://en.wikipedia.org/wiki/File: Solvay_conference_1927.jpg
- Image on slide 4 (Richard P. Feynman) -
https://upload.wikimedia.org/wikipedia/en/4/42/ Richard_Feynman_Nobel.jpg
- Image on slide 7 (development ladder) - M.H. Devoret, R.J.
Schoelkopf, Superconducting Circuits for Quantum Information: An Outlook, Science 8 March 2013, Vol. 339,
- no. 6124, pp. 1169-1174, DOI:10.1126/science.1231930
- Image on slide 9 (SMBC comic) -
http://www.smbc-comics.com/?id=1623
- Image on slide 11 (comparison) -
http://download2.cerimes.fr/canalu/documents/ fuscia/quantum.turing.test_13249/kashefi.pdf
SLIDE 129 References
- Image on slide 12 (atom energy levels) - https:
//dr282zn36sxxg.cloudfront.net/datastreams/f-d% 3A96a9d2797f6e33d4a10187aeef0abdb52be51b8602c4fda58fa9768d% 2BIMAGE_THUMB_POSTCARD%2BIMAGE_THUMB_POSTCARD.1
- Image on slide 12 (photon polarization) -
https://physics.aps.org/articles/v5/86
- Image on slide 12 (optical paths) -
https://www.quora.com/ What-is-a-physical-example-of-a-unitary-operator-in-quantum- answer/Bingjie-Wang-2
14 (D-Wave chip) - http://www.aboutai.com/2014/07/11/ how-d-wave-built-quantum-computing-hardware-for-the-next-
- Image on slide 14 (Optics) -
http://www.ichf.edu.pl/res/CL/research_en.html
- Image on slide 14 (Optical chip) - http://www.bristol.ac.
uk/news/2015/april/photonic-chip.html
SLIDE 130 References
- Image on slide 14 (Ion trap top) - http://jqi.umd.edu/
sites/default/files/images/razoriontrap-001.jpg
- Image on slide 14 (Ion trap bottom) - http://www.nist.
gov/pml/div688/microwave-quantum-081011.cfm
- Image on slide 18 (Huge atom) -
http://www.economist.com/node/6877077
- Image on slide 18 (quantum money) - https://a248.e.
akamai.net/f/1097/1823/7m/deliveryimages.acm.org/ 10.1145/2250000/2240258/figs/f2.jpg
- Image on slide 19 (Death star) -
https://techrepublic-a.akamaihd.net/hub/i/2015/ 05/07/7663b419-f49c-11e4-940f-14feb5cc3d2a/death_ star_schematic.gif
- Image on slide 20 (Lightsaber) -
http://vignette3.wikia.nocookie.net/starwars/ images/4/41/KunLightsaberSchematic.jpg/revision/ latest?cb=20110717211606
SLIDE 131 References
- Image on slide 21 (BB84) - http:
//swissquantum.idquantique.com/IMG/jpg/bb84.jpg
- Image on slide 22 (Device independence) -
https://physics.aps.org/articles/v7/99
- Image on slide 23 (idquantique website) -
http://www.idquantique.com/quantum-safe-crypto/
- Image on slide 24 (QKD rack) - http://www.vad1.com/
photo/stock/a299-3-boxes-labeled.pdf
- Image on slide 25 (China network) - http:
//2014.qcrypt.net/wp-content/uploads/Zhao.pdf
- Image on slide 25 (US network) -
http://www.theverge.com/2014/11/18/7214483/ quantum-networks-expand-across-three-continents