Open discussions on specific topics selected by the Software Working Group and selected from the list of SWG Topics For Discussion.
Quantum Computing at NCSA
Moderated by Santiago Nunez-Corrales
Quantum computing has quickly risen to prominence during the last five years thanks to the increasing number of platforms and software development kits demonstrating its potential advantages for certain classes of problems. In addition, the relationship between HPC and quantum computing has become more developed, similar to how GPUs operate in the HPC space. Quantum devices, compared to their classical counterparts, tap into a different set of laws of nature and logic that require adjustment of our notions of what computation is. In this first SWG session on quantum computing, we will introduce the conceptual basis required to distinguish why quantum is different from classical computing, and how it may be advantageous for certain classes of problems known to be infeasible for classical computers. We will introduce quantum algorithms by solving two known problems: adding two quantum binary digits with carry, and teleporting information about a quantum state.
Recording: https://uofi.box.com/s/6lvsj936nmi1qn7unw2u087c7z4jqd0p
Slides:
Attendees:
Santiago Nunez-Corrales
Rebecca Eveland
KJ Naum
Jong Lee
Bing Zhang
Chen Wang
Nick Kowalik
Rashmil Panchani
Sandeep Puthanveetil Satheesan
Sara Lambert
Ya-Lin Yang
Marcos Frenkel
Wendy Shan
Roland Haas
Max Burnette
Kenton McHenry
Don Petravick
Visu Monaharasan
Minu Mathew
Jong Lee
Lisa Yanello
Bruno Abreu
Andrew Manning
Kastan Day
Discussion:
Today's topic will be conceptual. A bit of history was given, then a summary of how QC has grown and it continually to rapidly evolved.
What do we mean by quantum computing?
What is a computer? turning patterns of energy into other patterns of energy. an electronic device for storing and processing data, typically in binary form, according to instructions given to it in a variable program.
- Finite State
- Terminating Program
- Input
- Output
- State Uniqueness
- Determinism
- Non-Destructive reads
- Copy-ability
- Coherence
- Noise tolerance
- Irreversibility
- Locality
Church-Turing Thesis Expanded; David Deutsch
Postulates of quantum mechanics ( see slides )
Quantum states exhibit simultaneity (no single state)
Gates = Algebra
Quantum states - Spinors w/Clifford Algebras
Simulating quantum information processing with classical computer is infeasible.
Qubits vs Classical Bits 
Terminating program, inputs and outputs with the principle of equivalence or hardware and software
Quantum computing is (quasi) probabilistic.
Quantum states are not measurable to arbitrary accuracy
Quantum states cannot be copied - there is a no-cloning theorem
Quantum states decohere - coherence time: How long can a quantum state live? They decay over time.
This happens because the evolution of a quantum state is dictated by a Fokker-Planck equation. Probability constantly evolves in a quantum state
Quantum states are sensitive to noise. Quantum circuits must be shielded against thermal, mechanical and electromagnetic noise.
Quantum circuits are inevitably subject to intrinsic quantum noise, shot noise, and decoherence noise?
Classical circuits dissipate heat = thermal noise
Approximation
Future quantum systems may have implications for energy consumption
Quantum state may be non-local
Quantum entanglement allows dense supercoding
Case 1 -
- 1. a quantum full adder; expand the classical full adder
- 2. expand the classical circuits; make the circuit reversible
- 2. classical gates → quantum gates
Use the minimum amount of quantum bits - think quantum from the start.
Case 2 - quantum teleportation of arbitrary quantum state
- attempt classical communication. quantum algorithms can u se classical information
- Use entanglement to facilitate the exchange
- Use entanglement is the basis of quantum cryptography
Quantum machines are different beasts!
Classical - space and time
Quantum - space, time, superposition, coherence, entanglement, interference
Action Items:
There is a slack channel #quantum-computing
IBM quantum and https://qiskit.org
More people are getting involved in quantum at NCSA!
There were a great deal of questions at the end of the talk
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