QUBIT VERSUS BIT

  • View
    34

  • Download
    0

Embed Size (px)

DESCRIPTION

QUBIT VERSUS BIT. Lev Vaidman. Zion Mitrani Amir Kalev. Phys. Rev. Lett. 92 , 217902 (2004),. quant-ph/0406024. 23 August 2004, Cambridge. BIT. QUBIT. q, f. BIT. QUBIT. q, f. TO WRITE q, f. TO WRITE 0, 1. TO READ 0, 1. TO READ 0, 1. NO!. N. N. N. N. N. N/2. - PowerPoint PPT Presentation

Text of QUBIT VERSUS BIT

  • QUBIT VERSUS BIT23 August 2004, CambridgeLev Vaidmanquant-ph/0406024 Zion MitraniAmir KalevPhys. Rev. Lett. 92, 217902 (2004),

  • QUBITBITq, f

  • NNNN/2NNN/2DENSE CODING NNKNOWN QUBITS

  • TeleportationUNKNOWN QUBIT2 BITS

  • TeleportationUNKNOWN QUBIT2 BITS 2

  • We cannot store and retrieve more than one bit in a qubit HOLEVOWhat can we do with a qubit that we cannot do with a bit?

  • We cannot store and retrieve more than one bit in a qubit HOLEVOWhat can we do with a qubit that we cannot do with a bit?Tasks with 2 possible outcomes?orWe know

  • We cannot store and retrieve more than one bit in a qubit HOLEVOWhat can we do with a qubit that we cannot do with a bit?Tasks with 2 possible outcomes?orWe know

  • We cannot store and retrieve more than one bit in a qubit HOLEVOWhat can we do with a qubit that we cannot do with a bit?Tasks with 2 possible outcomes?orWe know

  • Measurement of the parity of the integral of a classical field Galvao and Hardy,Phys. Rev. Lett. 90, 087902 (2003)

  • Measurement of the integral of a classical field AB

  • Measurement of the integral of a classical field Binary representation of I . . . . . . 1 0 1 AB

  • . . . . . . 0 0 0 0 0 1 0 1

  • What can we do with bits passing one at a time? AB

  • What can we do with bits passing one at a time? ABorWe can write a real number in a bit as the probability of its flip

  • Uncertainty in measurement with bits Optimization for The number of bits for findingis

  • Uncertainty in measurement with bits Optimization for The number of bits for findingis The number of qubits for findingisQuantum method yields precise result for integer I if

  • Measurement of the integral of a classical field

  • Measurement of the integral of a classical field ABN qubits

  • Measurement of the integral of a classical field ABN entangled qubits Peres and Scudo PRL 86 4160 (2001)

  • But the digital method works much better! . . . . . . AB

  • Quantum uncertainty Classical uncertainty

  • Information about I in N qubits is inCan we use a single particle in a superposition of N different states instead?. . . . . . . . .

  • Information about I in N qubits is inCan we use a single particle in a superposition of N different states instead?. . . . . . . . .

  • Measurement of the integral of a classical field with a single particle in a superposition of states

  • Measurement of the integral of a classical field with a single particle in a superposition of states

  • Measurement of the integral of a classical field with a single particle in a superposition of states Measurement yields

  • The probability of the error

  • N qubits Single particle

  • Binary representation of k N qubits Single particle

  • Binary representation of k N qubits Single particleInteraction

  • N qubits Single particlestates

  • Measurement of the integral of a classical field with N bits running together AB

  • How to read a string of length out of strings using a single particle?

  • How to read a string of length out of strings using a single particle? 10

  • How to read a string of length out of strings using a single particle? 10Bits instead We need at least

  • What else can we do with the quantum phase?