Quantum Computers New Generation of Computers Part 8 Quantum Error Correction by Prof. Lili Saghafi

© Prof. Lili Saghafi , All Rights Reserved
Quantum Computers
New Generation of Computers
PART 8
Quantum Error Correction
Professor Lili Saghafi
2015

AGENDA
• Decoherence
• Fault-Tolerant Correction
• Nuclear Magnetic Resonance
• Quantum Error Correction
• Future Quantum Internet
• Quantum Networkers
• Silicon Semiconductors Limits
• Diamond-Driven Technology
• Diamond Crystals
• Interference
• Niobium
• What Is Graphene
• Scanning Tunneling Microscope
• Weyl Fermion
• Massless Particle Known As A Weyl Fermion
• Quasiparticle
• “Middle Man” Nuclei
• Hyperfine Interaction
• Computing Power Of A Huge Number Of Parallel Universes
• Many-Worlds Interpretation (Mwi)
• Quantum Computing Power

DECOHERENCE
• One of the biggest hurdles faced by quantum
computing researchers is called decoherence —
the tendency of quantum systems to be
disturbed.
• This vulnerability to noise leads to errors, which
can be overcome by quantum error correction.
• Because error correction techniques are
themselves susceptible to noise, it is crucial to
develop fault-tolerant correction.
• liquid-state nuclear magnetic resonance
3

Nuclear Magnetic Resonance (NMR)
• Nuclear Magnetic Resonance (NMR)
Spectroscopy uses the electromagnetic
radiation of radio waves to probe the local
electronic interactions of a nucleus.
• NMR is a non-destructive technique and has
found uses in fields of medicine, chemistry,
and environmental science.

DECOHERENCE
• information is physical and cannot exist
without a physical representation.
• In recent decades, the relationship between
physics and information has been revisited
from a new perspective: could the laws of
physics play a role in how information is
processed? The answer appears to be yes.
5

• If information is represented by systems such as
nuclear spins governed by the laws of quantum
mechanics, an entirely new way of doing
computation, quantum computation (QC),
becomes possible.
• Quantum computing is not just different or new;
it offers an extraordinary promise, the capability
of solving certain problems which are beyond the
reach of any machine relying on the classical laws
of physics

• It is already in work , in 2015 , D-Wave a
Canadian company produce a Quantum
Computer with 1000 Qubits in work.
• AMD Quantum Computers has been already in
the market

QUANTUM COMPUTING of D-Wave
systems

AMD's radical Project Quantum PC, a
showcase for its new Fiji GPU
there’s some serious use of machined aluminum in
the Project Quantum chassis.
Project Quantum PC held
by Professor Xavier gives
you an idea of large it is.

This render of Project Quantum
shows how tightly packed
components are.
This CAD image of the
radiator and water
blocks give you an idea
of the interior layout.

It’s all copper cold plates or water blocks for the
Project Quantum that keep it cool.
the Project Quantum demo
machines were indeed build
with Intel Core i7-4790K
CPUs rather than AMD’s own
APU or CPUs.
the 9-inch PCB dual Fiji board made
for the Project Quantum PC.

Quantum Error Correction Had To
Overcome Three Important Obstacles:
• (1) the no-cloning theorem, which states that
it is not possible to copy unknown quantum
states
• (2) measuring a quantum system affects its
state
• (3) errors on qubits can be arbitrary rotations
in Hilbert space, compared with simple bit
flips for classical bits.
12

Quantum Error Correction
• Quantum error correction requires many extra
operations and extra qubits (ancillae),
however, which might introduce more errors
than are corrected, especially because the
effect of decoherence increases exponentially
with the number of entangled qubits, in much
the same manner that multiple quantum
coherences decay exponentially faster than
single quantum coherences.
13

• Therefore, a second surprising result was that
provided the error rate (probability of error
per elementary operation) is below a certain
threshold, and given a fresh supply of ancilla
qubits in the ground state, it is possible to
perform arbitrarily long quantum
computations

New Perspective On NMR, Nuclear
Magnetic Resonance
• The possible payoff for successful quantum
computing is tremendous: to solve problems
beyond the reach of any classical computer.
• It is not clear at this point whether quantum
computers will fulfill this promise, but in any case
quantum computing has already provided an
exciting new perspective on NMR and, more
broadly, on the connection between physics,
information and computation.
15

The atom’s quantum information is written onto the polarization state of the
photon. Graphics: Harald Ritsch

• Physicists directly transferred the quantum
information stored in an atom onto a particle of light.
• Such information could then be sent over optical
fiber to a distant atom.
• Not only do optical fibers transmit information every
day around the world at the speed of light, but they
can also be harnessed for the transport of quantum
information.
• Thanks to the strange laws of quantum mechanics,
quantum computers would be able to carry out
certain computational tasks much faster than
conventional computers.

• But we are still missing viable interfaces with
which quantum information can be
transferred over optical channels from one
computer to another.
• What makes the construction of these
interfaces especially challenging is that the
laws of quantum mechanics don’t allow
quantum information to be simply copied.

FUTURE QUANTUM INTERNET
• a future quantum internet – that is, a network of
quantum computers linked by optical channels –
would have to transfer quantum information onto
individual particles of light, known as photons.
• These photons would then be transported over
an optical-fiber link to a distant computing site.
• quantum information has been directly
transferred from an atom in an ion trap onto a
single photon.

Quantum networkers
• First trap a single calcium ion in an ion trap and
position it between two highly reflective mirrors.
• We use a laser to write the desired quantum
information onto the electronic states of the
atom
• The atom is then excited with a second laser, and
as a result, it emits a photon.
• At this moment, we write the atom’s quantum
information onto the polarization state of the
photon, mapping it onto the light particle.

Quantum networkers
• The photon is stored between the mirrors until it
eventually flies out through one mirror, which is
less reflective than the other.
• The two mirrors steer the photon in a specific
direction, effectively guiding it into an optical
fiber
• The quantum information stored in the photon
could be conveyed over the optical fiber to a
distant quantum computer, where the same
technique could be applied in reverse to write it
back onto an atom.

On one silicon chip there are 3 billion of these
transistors, 5000 times smaller than human
hair
22

Silicon is the second most abundant
material on the earth
23

Common Sand
24

Silicon Semiconductors Limits
• Firstly, there’s the issue of heat.
– Silicon semiconductors require a great deal of heat
management which in turn results in major energy
waste.
• Secondly the size and speed of electronic
devices are limited by the performance
capabilities of silicon.
– At this point, it is difficult – if not impossible – to
create smaller or faster devices while still relying on
silicon semiconductors
25

silicon wafer
26

• Made in silicon
• Single atom , electron in silicon, and encode
are information in Qubits
• Good thing is that Silicon does not interact
with electrons
27

Diamond-driven Technology
• The limitations of silicon-based technology is
one of the biggest factors in the rise of
diamond-based technology.
• The element silicon has been the primary
semiconductor in electronics for over half a
century.
• Unfortunately, silicon semiconductors come
with a few key issues.
28

DIAMOND CRYSTALS
• Tiny, nanoscale mirrors were constructed to trap
light around atoms inside of diamond crystals,
acting like a series of funhouse mirrors.
• The mirrored cavities in the crystal allow light to
bounce back and forth up to 10,000 times,
enhancing the normally weak interaction
between light and the electronic spin states in the
atoms.
• As a result, a 200-microsecond spin-coherence
time – how long the memory encoded in the
electron spin state lasts – was produced.

DIAMOND CRYSTALS
trap light around atoms inside of diamond
crystals
• The enhanced interactions between light
and atoms and the extended spin-coherence times are
essential steps toward realizing real-world quantum
memories and, hence, quantum computing systems,
which could solve some problems faster than
conventional systems.
• Additionally, these advances could significantly impact
the development of high-security, long-distance,
cryptographic fiber optic communication networks.

Trap Light Around Atoms Inside Of
Diamond Crystals
• Nanoscale mirrored cavities that trap light
around atoms in diamond crystals increase the
quantum mechanical interactions between
light and electrons in atoms.
• Such interactions are essential to the creation
and the connection of memory for quantum
computers.
•

• research, performed at the Massachusetts
Institute of Technology (MIT) and the Center for
Functional Nanomaterials at the U.S. Department
of Energy's Brookhaven National Laboratory, has
demonstrated a new process to construct such
diamond nanocavities in which memories are
encoded inside the electronic spin states of an
atomic system, with a memory time exceeding
200 microseconds.

• This improvement in the coherence time is more
than two orders of magnitude better than
previously reported times for cavity-coupled
single quantum memories in solid state systems.
• The fabrication of the optical cavities relied on a
new silicon hard-mask fabrication process that
applies mature semiconductor fabrication
methods for patterning high-quality photonic
devices into unconventional substrates.

Interference
• The large loop in the diagram is made from a
metal called niobium (in contrast to
conventional transistors which are mostly
made from silicon).
• When this metal is cooled down, it becomes
what is known as a superconductor, and it
starts to exhibit quantum mechanical effects.
35

Niobium
• The primary mineral from which niobium is
obtained is known as pyrochlore.
• The world's largest deposit is located in Araxá,
Brazil and is owned by Companhia Brasileira
de Metalurgia e Mineração (CBMM).
• The reserves are enough to supply current
world demand for about 500 years, about 460
million tonnes.
36

Niobium, formerly columbium, is a chemical element with symbol Nb and atomic
number 41. It is a soft, grey, ductile transition metal, which is often found in the
pyrochlore mineral, the main commercial source for niobium, and
columbite. Wikipedia
37

WHAT IS GRAPHENE?
• Graphene is a material made of a single layer
of carbon atoms arranged in a honeycomb
lattice.
• The discovery of graphene at the University of
Manchester in 2003 earned Andre Geim and
Konstantin Novoselov the Nobel Prize in
Physics due to its outstanding properties.

GRAPHENE is single atom, is 1000 time faster than silicon, pencil lead, one
atom thick, on scotch tape
39

GRAPHENE
40

Silicon on top of GRAPHENE
41

Scanning Tunneling Microscope
The only technology that exist now to build these Qubits
42

Principal of Scanning tunneling
microscope
43

microscope
44

microscope
45

microscope
46

Quantum Tunnel Effect And Tunneling
Microscope / Video
47

Scanning Tunneling Microscope
• How do we image or manipulate atoms now the
only technology is Scanning tunneling microscope
• It has fine metal tips , when you bring it down to
atom surface , you apply a voltage , it creates a
current, it keeps current constant , move that tip
through the atom,
• as it move it deflect in height ,
• from that you can image the atom on the surface,
and then
• you raster- scanner it , rather like a television
screen
49

Surface studies with a scanning
tunnelling microscope
50

51

52

WEYL FERMION
• particle theorized more than 85 years ago
• the "Weyl fermion", is a strange but stable
particle that has no mass, behaves as both matter
and anti-matter inside a crystal, and is claimed to
be able to create completely massless electrons.
• Scientists believe that this new particle may
result in super-fast electronics and significant
inroads into novel areas of quantum computing.

What is WEYL FERMION?
• Weyl fermions were first mooted in 1929 by
physicist and mathematician Hermann Weyl
• There are two types of particles that make up
the universe and everything in it: fermions
and bosons.
• fermions are all the particles that make up
matter (for example, electrons),
• bosons are all the particles that carry force
(for example, photons).

MASSLESS PARTICLE KNOWN AS A
WEYL FERMION
• The discovery of a massless particle known as
a Weyl fermion may lead to new types of
quantum computing, according to
researchers.
• The quasiparticle properties of the Weyl
fermion mean it could find applications in
quantum computers more resistant to
disruption.

QUASIPARTICLE
• As a quasiparticle – that is, a particle that exists
inside a solid (in this instance) but acts as if it
were a weakly interacting particle in free space –
the Weyl fermion is massless and has a high
degree of mobility.
• This is because, as the particle's spin is both in
the same direction as its motion (known in
physics as "right-handed") and in the opposite
direction in which it moves ("left-handed"), it is
able to traverse through and around obstacles
that impede ordinary electrons.

basic building block of all electrons
• After more than 80 years, this fermion was
already there, waiting.
• It is the most basic building block of all
electrons.
• It is exciting that we could finally make it come
out following Weyl's 1929 theoretical
proposal.

Weyl fermions
• fermions such as electrons can collide with
each other, losing energy, and no two
fermions can share the same state at the same
position at the same time.
• Weyl fermions being massless, however, have
no such restrictions.

Weyl fermions
• Without mass, electrons created from Weyl
fermions would be able to move electric charge
in a circuit much more quickly than ordinary
electrons.
• In fact, according to latest research, electric
current carried by Weyl electrons in a test
medium is able to move at least twice as fast as
that carried by electrons in graphene and at least
1,000 times faster than in ordinary
semiconductors.

WEYL FERMIONS
• These are very fast electrons that behave like
unidirectional light beams and can be used for
new types of quantum computing.
• It's like Weyl fermions have their own GPS and
steer themselves without scattering

WEYL FERMIONS
• the Weyl fermion particle is able to move
electric charge inside electronics more quickly
than electrons due to its lack of mass.
• Weyl fermions offer new ways of encoding
quantum information as they are less prone to
interacting with their environment, thus
making them more stable.

WEYL FERMIONS
• Weyl materials are direct 3-D electronic
analogs of graphene, which is being seriously
studied for potential applications.

WEYL FERMIONS
• Weyl fermions could theoretically carry charge 1,000x
faster than ordinary semiconductors, and at least twice
as fast as wonder material graphene.
• Weyl fermions are the basic building blocks; you can
combine two Weyl fermions to make an electron
• Weyl fermions could be used to solve the traffic jams
that you get with electrons in electronics – they can
move in a much more efficient, ordered way than
electrons.
• They could lead to a new type of electronics we call
'Weyltronics'.

Weyl fermions

An Intermediary To Transmit
Information In Quantum
Computing “Middle Man”
Nuclei

Quantum computer storage may require the help of an
intermediary to transmit information
• We need system that could store quantum
information for longer times, which is critical
for the future of quantum computing.
• Quantum computing—which aims to use
particles on the atomic scale to make
calculations and store the results—has the
potential to solve some key problems much
faster than current computers.
• stable long enough to make the calculations.

• While this is an extremely short time frame,
only thousandths of a second, the particles
involved are so small that they are easily
influenced by their surroundings.
• If the motion of the particles is disturbed,
even a little, it throws off the whole
calculation.

NUCLEI
• Nuclei (nooh-klee-eye) The small, dense
center of the atom.
• The nucleus is composed of protons and
neutrons and has a positive electrical charge.
• Note: Nuclear physics deals with the
composition and structure of the nucleus.

"MIDDLE MAN"
• Nuclei are promising contenders for quantum
memory because they are not easily influenced
by their surroundings.
• However, that also makes them extremely
difficult to manipulate.
• Many tried with little success
• Instead of trying control the nucleus directly, the
researchers focused on a "middle man" of sorts –
the electrons orbiting the nucleus.

"MIDDLE MAN"
• The nucleus has a tiny internal magnet, called a "magnetic
moment," and the electrons orbiting around it also have
magnetic moments that are about 1,000 times larger.
• Those magnets interact with each other, which is called the
"hyperfine interaction.“
• hyperfine interaction
– When the nucleus of an atom has a non-zero magnetic
moment, the magnetic field of the nucleus interacts with
electrons in the atom.
– This interaction is called the hyperfine interaction, and leads to
finely spaced atomic energy levels called hyperfine structure.

Manganese
• The hyperfine interaction is stronger in some
materials than others.
• The researchers found that a crystal made of
manganese and some other elements has a
strong hyperfine interaction.
• This enabled them to manipulate the nuclei
by first targeting the electrons.

quantum state of the photon
• Information in quantum computing is conveyed by
photons, which are individual particles of light, which
also make up other nonvisible electromagnetic waves,
such as ultraviolet and microwaves.
• The information transmitted is actually the quantum
state of the photon.
• The quantum state of the photon needs to be
transferred to another particle so it will last long
enough for the computation to take place.

• In an experiment, the researchers beamed
microwaves through a manganese carbonate
crystal.
• The magnetic field of the microwaves
interacted with the magnetic moments of the
electrons that are orbiting around the nuclei
of the manganese atoms.
•

• The electrons' movements started to change,
which in turn altered the movement of the
nuclei because they are connected by the
hyperfine interaction.
• The quantum state of the microwave photon
was transferred to the nuclei when the
nuclei's internal magnets flipped to point in
the opposite direction.

Strong Coupling Between Microwave
Photons And Nuclear Spins
• This all has to happen very quickly before the quantum
state of the photon changes.
• To transmit the information and flip the nuclei fast
enough, there has to be a strong connection between
the microwaves and nuclei via the electrons.
• "To our knowledge, our experiment is the first
demonstration of the strong coupling between
microwave photons and nuclear spins," Leonid
Abdurakhimov

• cool down the system to nearly -273 C, or -500 F,
to see if they can strengthen the connection and
extend the time information can be stored by
minimizing temperature fluctuations.
• "We are making the first and important steps
towards using an ensemble of nuclear spins for
quantum memory," Konstantinov
• "We now have a whole class of materials that can
be used for this purpose.

computing power of a huge number of
parallel universes
• Future experiments promise to be quite
exciting
• quantum computers can be so efficient: they
harness the computing power of a huge
number of parallel universes.

Many-Worlds Interpretation (MWI)
• First introduced in 1957 by theoretical
physicist Hugh Everett, the Many-Worlds
Interpretation (MWI) of quantum physics says
that the weird and counter-intuitive quantum
superpositions extend across parallel
universes.

Many-Worlds Interpretation (MWI)
• A qubit in a quantum superposition of zero
and one states exists in two parallel universes.
• Similarly, two qubits require four parallel
universes, and so forth.
• Doing the math, it's easy to see that a system
of 1000 qubits spans a huge number of
parallel universes.

D-Wave quantum computers
• Google bought the first D-Wave quantum
computers, and Google researchers consider
quantum computing as a path to Artificial
Intelligence (AI), with first practical
applications to image recognition, machine
learning and deep learning.

Computing with Parallel Universes
Steve Jurvetson
• The only physical explanation of how quantum
computing works is that it uses the
computational resources of parallel universes
says Jurvetson in the video
Youtube :Computing with Parallel
Universes

QUANTUM COMPUTING POWER
• Since the number of parallel universes whose
computing power is harnessed by a quantum
computer increases exponentially with the
number of qubits, a quantum computer with a
few thousands of qubits could have a
computing power greater than all existing
computers combined, and adding even more
qubits could result in a machine with more
computational power than the entire
universe.

• If quantum computers keep doubling the
number of qubits every few years, Moore's
Law - the observed doubling in performance
of computer systems every two years - would
become even faster.
• "It's a Moore's Law on top of Moore's Law,"
says Jurvetson commenting the image ,titled
"Rose's Law" after D-Wave's founder and CTO
Geordie Rose.

• the practical difficulty of building quantum
computers increases exponentially with the
number of qubits, so there is the possibility
that quantum computing research might run
into a barrier.

D-Wave Systems: the firm's 512-qubit
processor

• Recently quantum computing company D-
Wave Systems announced that it had broken
the 1000 qubits barrier - an important
breakthrough

Thank you!
Great Audience
Professor Lili Saghafi
proflilisaghafi@gmail.com

References, Images Credit
• Internet and World Wide Web How To Program, 5/E , (Harvey & Paul) Deitel & Associates
• New Perspectives on the Internet: Comprehensive, 9th Edition Gary P. Schneider Quinnipiac
University
• Web Development and Design Foundations with HTML5, 6/E, Terry Felke-Morris, Harper
College
• SAP Market Place https://websmp102.sap-ag.de/HOME#wrapper
• Forbeshttp://www.forbes.com/sites/sap/2013/10/28/how-fashion-retailer-burberry-keeps-
customers-coming-back-for-more/
• Youtube
• Professor Saghafi’s blog https://sites.google.com/site/professorlilisaghafi/
• http://www.slideshare.net/lsaghafi/
• Timo Elliot
• https://sites.google.com/site/psuircb/
• http://fortune.com/
• Theoretical Physicists John Preskill and Spiros Michalakis
• Institute for Quantum Computing https://uwaterloo.ca/institute-for-quantum-computing/
• quantum physics realisation Data-Burger, scientific advisor: J. Bobroff, with the support of :
Univ. Paris Sud, SFP, Triangle de la Physique, PALM, Sciences à l'Ecole, ICAM-I2CAM
• Max Planck Institute for Physics (MPP) http://www.mpg.de/institutes
• D-Wave Systems
• References
92

References, Images Credit
• Frank Wilczek. Physics in 100 Years. MIT-CTP-4654, URL = http://t.co/ezfHZdriUp
• William Benzon and David G. Hays. Computational Linguistics and the Humanist. Computers and the Humanities 10: 265 –
274, 1976. URL =https://www.academia.edu/1334653/Computational_Linguistics_and_the_Humanist
• Stanislaw Ulam. Tribute to John von Neumann, 1903-1957. Bulletin of the American Mathematical Society. Vol64, No. 3,
May 1958, pp. 1-49, URL = https://docs.google.com/file/d/0B-5-JeCa2Z7hbWcxTGsyU09HSTg/edit?pli=1
• I have already discussed this sense of singualirty in a post on 3 Quarks Daily: Redefining the Coming Singularity – It’s not
what you think, URL = http://www.3quarksdaily.com/3quarksdaily/2014/10/evolving-to-the-future-the-web-of-culture.html
• David Hays and I discuss this in a paper where we set forth a number of such far-reaching singularities in cultural evolution:
William Benzon and David G. Hays. The Evolution of Cognition. Journal of Social and Biological Structures 13(4): 297-320,
1990, URL = https://www.academia.edu/243486/The_Evolution_of_Cognition
• Neurobiology of Language – Peter Hagoort on the future of linguistics, URL =http://www.mpi.nl/departments/neurobiology-
of-language/news/linguistics-quo-vadis-an-outsider-perspective
• See, for example: Alex Mesoudi, Cultural Evolution: How Darwinian Theory Can Explain Human Culture & Synthesize the
Social Sciences, Chicago: 2011.
• Lewens, Tim, “Cultural Evolution”, The Stanford Encyclopedia of Philosophy (Spring 2013 Edition), Edward N. Zalta (ed.), URL
= http://plato.stanford.edu/archives/spr2013/entries/evolution-cultural/ Cultural evolution is a major interest of mine.
• Here’s a collection of publications and working papers, URL =https://independent.academia.edu/BillBenzon/Cultural-
Evolution
• Helen Epstein. Music Talks: Conversations with Musicians. McGraw-Hill Book Company, 1987, p. 52.
• [discuss these ideas in more detail in Beethoven’s Anvil, Basic Books, 2001, pp. 47-68, 192-193, 206-210, 219-221, and in
• The Magic of the Bell: How Networks of Social Actors Create Cultural Beings, Working Paper, 2015, URL
=https://www.academia.edu/11767211/The_Magic_of_the_Bell_How_Networks_of_Social_Actors_Create_Cultural_Beings
• http://www.pcworld.com/article/2937337/meet-amds-radical-project-quantum-pc-a-showcase-for-its-new-fiji-gpu.html
• http://www.quantiki.org/wiki/Liquid-state_NMR
• Publication: Quantum-state transfer from an ion to a photon. A. Stute, B. Casabone, B. Brandstätter, K. Friebe, T. E. Northup,
R. Blatt. Nature Photonics 2013 DOI: 10.1038/NPHOTON.2012.358 -
http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2012.358.html

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