The Circuit Perspective of Digital Quantum SwitchingThe Circuit Perspective of Digital Quantum Switching

郭斯彥郭斯彥 ((Sy-Yen Kuo)Sy-Yen Kuo)Dept. of Electrical EngineeringDept. of Electrical Engineering

National Taiwan UniversityNational Taiwan University

Workshop on Quantum Information ScienceWorkshop on Quantum Information Science

Oct 18-19, 2002, Tainan, TaiwanOct 18-19, 2002, Tainan, Taiwan

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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Elementary Quantum CircuitsElementary Quantum Circuits

• Some basic quantum boolean gatesSome basic quantum boolean gates

• Phase shift and rotationPhase shift and rotation

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UniversalityUniversality

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Straightforward ReplacementStraightforward Replacement

• Pros and consPros and cons

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Implementation of Qubit ExchangeImplementation of Qubit Exchange

• An ‘exchange’ gate can be implemented using 3 An ‘exchange’ gate can be implemented using 3 CN gatesCN gates

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Case 1

Case 2

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Decomposition of CyclesDecomposition of Cycles

• A cycle can be implemented using two sets of A cycle can be implemented using two sets of ‘exchange’ gates‘exchange’ gates

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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Space Switching v.s. Time SwitchingSpace Switching v.s. Time Switching

• Space complexitySpace complexity• Time complexityTime complexity

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Space Switching v.s. Time SwitchingSpace Switching v.s. Time Switching

• Space complexitySpace complexity• Time complexityTime complexity

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Circuit Switching vs. Packet SwitchingCircuit Switching vs. Packet Switching

• Data dependency & Output contentionData dependency & Output contention• Buffering strategyBuffering strategy

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Unicasting v.s. MulticastingUnicasting v.s. Multicasting

• BandwidthBandwidth• ComplexityComplexity

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Connection Digraph -- Connection Digraph -- Loopbacks and Null pointsLoopbacks and Null points

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Connection Digraph -- Connection Digraph -- QueueQueue

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Connection Digraph -- Connection Digraph -- CycleCycle

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Connection Digraph -- Connection Digraph -- TreeTree

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Connection Digraph -- Connection Digraph -- ForestForest

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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Quantum Domain SwitchingQuantum Domain Switching

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GuidelinesGuidelines

• Convert each connection digraph into cycles or loConvert each connection digraph into cycles or loopbacksopbacks

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Cycle Extraction and Link RecoveryCycle Extraction and Link Recovery

• Cycle extraction and Link recovery are executed Cycle extraction and Link recovery are executed recursivelyrecursively

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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An Example of UnicastingAn Example of Unicasting

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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An Example of Multicasting (1/2)An Example of Multicasting (1/2)

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An Example of Multicasting (2/2)An Example of Multicasting (2/2)

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ContentsContents

• Quantum CircuitsQuantum Circuits

• Digital SwitchingDigital Switching

• Quantum SwitchingQuantum Switching

• Unicast Quantum SwitchingUnicast Quantum Switching

• Multicast Quantum SwitchingMulticast Quantum Switching

• SummarySummary

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SummarySummary

• We show how digital switching can be We show how digital switching can be performed in the quantum domain.performed in the quantum domain.

• Quantum switchingQuantum switching– Blocking rateBlocking rate– Space complexity Space complexity – Time complexityTime complexity– Line SpeedLine Speed– Total CapacityTotal Capacity