quantum packet switching
Download
Skip this Video
Download Presentation
Quantum Packet Switching

Loading in 2 Seconds...

play fullscreen
1 / 18

Quantum Packet Switching - PowerPoint PPT Presentation


  • 150 Views
  • Uploaded on

Quantum Packet Switching. A. Yavuz Oruç Department of Electrical and Computer Engineering University of Maryland, College Park. Introduction. What :. The goal of our research is to use the unique properties of quantum systems to explore the design of efficient and novel switching systems.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Quantum Packet Switching' - gayle


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
quantum packet switching
Quantum Packet Switching

A. Yavuz Oruç

Department of Electrical and Computer Engineering

University of Maryland, College Park

introduction
Introduction

What:

  • The goal of our research is to use the unique properties of quantum systems to explore the design of efficient and novel switching systems

Why:

  • Quantum computing is an emerging and exciting field of research and its application to designing switching networks presents a challenging and interesting research problem
  • This investigation could lead to new insights into switch design because of the utilization of quantum properties like superposition and entanglement
how is quantum switching different
How is quantum switching different?
  • Quantum systems can operate simultaneously on a superposition of multiple states, giving inherent parallelism.
  • They also provide inherent randomization which has been an important tool in many classical networks
  • Can manipulate probability amplitudes via quantum circuits
  • Phenomenon of entanglement can be used to create correlation between random states: this has no classical analogue.
quantum computing
Quantum Computing
    • Classical bit: 0 or 1 only
    • Qubit can be in a superposition of both: where and
    • Measurement (w.r.t.) basis ( , ) affects the state or collapses it and we get 0 or 1 where
  • Superposition implies both 0 and 1 states are encoded in qubit. In other words, 0 and 1 coexist within a qubit until it is collapsed to one of the two values.

What if bits were “superposed” together?

quantum gates
Quantum Gates
  • A qubit is a vector in , i.e.,
  • Operations on qubits done by quantum gates: all gates are unitary transformations.
  • Gates represented by unitary matrices, e.g., Hadamard
  • Unitary evolution of qubits implies that all quantum computations arereversible:
multi qubit system
Multi-qubit system
  • State of multi-qubit system obtained by taking tensor product of individual qubit vectors

equivalently,

  • Same applies for multiple qubits, i.e., an n-qubit quantum system can be a superposition of 2nn-bit binary strings.
why superpose bits
Why superpose bits?
  • Superposition provides a natural process for parallel computations by way of unitary transformations on qubits.
  • What happens is that the operations which we would perform on a string of binary bits in classical computing can be applied to all such strings all at once.
  • These strings can represent numbers in a spreadsheet, vertices in a graph, instructions in computer programs, etc., and if processing such lists of strings or objects all at once can be useful then superposing bits makes sense.
  • In our case,we superpose permutations/sets of qubit packets.
entanglement of qubits

qubit-1

qubit-2

Entanglement of qubits
  • If a state with two or more qubits cannot be expressed as a tensor product of these qubits then qubits are entangled , e.g

We can describe the state of both qubits together but not one qubit individually: they are correlated or “entangled”

  • Can be thought of as a communication setup between the two qubits.
  • A very important application of entanglement is quantum teleportation.
classical networks

Blocking

000

000

001

000

0 => up

1 => down

000: up, up, up

001: up, up, down

001

001

010

010

011

011

100

100

101

101

110

110

111

111

Classical Networks
  • “Classical” sparse switches (with log N stages) have low cost but block routes
  • Easier routing on such switches, can use oblivious (self-routing) routing

Paths are unique => Blocking possible even for permutation assignments

can quantum parallelism help switching

000

000

001

000

001

001

010

010

011

011

100

100

101

101

110

110

111

111

Can quantum parallelism help switching?
  • Question: Can we use quantum parallelism to achieve better switch designs if packets are represented using quantum bits (qubits)?
quantum switch
Quantum switch

Prob. = |a|2

c=1

Quantum Switch

Prob. = |b|2

c=0

Has a “combined” state in addition to classical switch states

Works as a classical switch when c is “0” or “1”

Classical Switch

Works in a superposition of “through” and “cross” states when control qubit c is in a superposition of “0” and “1”

Works in either “through” or “cross” states

quantum baseline network

= invalid

Prob=1/4

Quantum Baseline Network

Binary output address: used to set control qubit

  • All feasible permutations are present in parallel in output superposition
  • Observation collapses the state: classical result
  • How to increase probability of favorable outcome?

11

10

00

01

challenges

Routing

stage

Randomization

stage

Challenges

Two stage model (First approach):

  • Create a quantum superposition of packet permutations and drive it to a state in which the probability of permutations which can be easily/self routed in the next stage is maximized
  • Use entanglement to achieve above
  • Self-route the packet superposition at the output of the first stage.
  • All the permutations at the output of randomization stage gets routed in parallel.
  • With high probability desired permutation is observed
challenges1

Probability

filter

Routing

stage

Challenges…

Two stage model (Second approach):

  • Create a quantum superposition of packet permutations and route them.
  • Output state has desired output permutation with non-zero probability.
  • This is a randomized non-blocking network: any input permutation always gives desired permutation in output superposition state w/ prob. > 0
  • Use Grover search like approach on output state of previous stage to boost the probability of the desired output permutation.
  • With high probability desired permutation is observed
probability filter stage grover like search
Probability Filter Stage: Grover-like search
  • One Grover iteration consists of two blocks: Ua followed by Us
  • Ua flips the sign of the desired component and Us inverts the coefficients about the average, i.e.,

invert about avg.

Flip sign of a

applying quantum search for filtering permutation probabilities
Applying quantum search for filtering permutation probabilities
  • We apply quantum search on tag qubits.
  • There is one tag qubit per packet in a permutation. Each packet permutation in the superposition has a corresponding tag state of N qubits.
  • A tag qubit is reset by the routing stage when the corresponding packet is routed incorrectly.
  • We do a quantum search for tag state = , which corresponds to correct routing.
applying quantum search for changing permutation probabilities an example
Applying quantum search for changing permutation probabilities: an example
  • 1 iteration of Grover search for the tag state 1111 (corres. to desired output) on the output state of routing stage
  • Coefficients become and , i.e., Prob. = 49/50 and 1/200 respectively.

Desired output

  • tag qubit = 0

else tag qubit = 1

Routing Stage

11

00

00

11

00

10

01

10

01

11

01

10

10

10

01

00

10

00

11

01

11

01

00

11

Co-eff = 1/√2

Co-eff = 1/(2√2)

=>Prob. = 1/2

Self-route

=>Prob. = 1/8 each

Randomize

7/5√2

-1/10√2

concluding remarks
Concluding Remarks
  • Quantum mechanics provides an exciting research frontier for creating systems that can operate on large collections of data all at once. This, so called quantum parallelism, has the prospect to revolutionize packet switching leading to contention free packet switching.
  • Our research has just scratched the surface, and further exploration of quantum packet switching is likely to form the basis for quantum packet switching and routing systems.
ad