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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

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?