Quantum router

Quantum Router

Submitted by : Ms.YojanaME(CSE-I) : Roll No. - 01

Overview

• Definition

• Working of QR

• 1st Demonstration of QR

• Research

• Challenge

Definition

• Quantum is a discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents.

• It is an analogous discrete amount of any other physical quantity, such as momentum or electric charge.

• Router is a device which forwards data packets to the appropriate parts of a computer network

Working of QR

Contd…

• Fig. (A) Illustration of a genuine quantum router. The control photon can be in arbitrary superposition states with coecients c0; c1 that determine the path of the signal photon.

• Fig. (B) the entanglement-based approach to implementation of a genuine quantum router. With a bit of pre-shared entanglement, the quantum router can be realized with linear optical devices.

• The control coecients c0; c1 are imprinted through operation on the control photon alone with a polarization rotator and alter. The routing is realized with a polarization beam splitter (PBS) and a wave plate on the signal photon.

Contd…

• An experiment that demonstrates full function of a quantum router using entangled photons, where the paths of a single-photon pulse are controlled in a coherent fashion by polarization of another single photon. Through a projective measurement, the polarization of the control photon in arbitrary superposition states, leading to coherent routing of the target photon in quantum superposition of different paths. Demonstrate quantum nature of this router through optical measurements based on quantum state tomography and show an average fidelity of $(93.24pm 0.23)%$ for the quantum routing operation.

1st Demonstration of QR

Contd..

• Chinese physicists unveil a router that uses a quantum control signal to determine path of quantum data signal.

• Physicists have exploited the quantum nature of photons to transmit information for some time now. And in doing so they’ve discovered just how powerful quantum communication can be compared to the classical kind.  

• Instead of sending the 0s and 1s of digital code, quantum communicators can send information in a superposition of states that represent both 0s and 1s at the same time. What’s more, separate quantum objects such as a pair of photons can be entangled, which means they share the same existence even if they are widely separated. That leads to a form of quantum information that has no classical counterpart.

Research in QR

• Physicists Demonstrate Working Quantum Router, a Step Toward a Quantum Internet

• As we know silicon semiconductors, quantum computers are very much a technology of the future. Instead of the usual string of 1s and 0s, they'll be able to send both types of information at the same time, dwarfing their traditional counterparts. But one major problem is that they can only move through one optical fibre. To push more information through, they need a router.

Contd…

• In a quantum computer, photons ferry information to other sources. It's possible to send the photons directly through one fibre, but routing comes in when another fibre is needed. Like the router you probably own, a control signal reads the data then sends it to its destination. But dealing with unruly quantum particles is a little more complicated; when a signal is read it's also destroyed. So even though the data can be transferred with traditional methods, that doesn't offer the kind of data-transferring power quantum computing offers.

Contd…

• This new quantum router proves it's possible to truly guide a quantum signal. The information used is encoded in two different types of polarized photons (like 1s and 0s). Scientists then create a single photon that acts as both (the combined 1s and 0s). That photon is then broken down into two photons that share the combined state. The router picks up one to determine the route, then the other photon is used to transfer the information. A simple series of half mirrors guides the photons along the correct route.

Challenge

• Now after successful working & demonstration of Quantum Router partially by using theoretical knowledge, China want to run Quantum Internet in world gracefully within 5 years.