an investigation of quantum teleportation

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An Investigation of Quantum TeleportationShaifali Singhal1 Anjali Jain2 Anil Kr Gankotiya3 Kadambari Aggarwal 4

Department of Computer Science and EngineeringRaj Kumar Goel Institute of Technology for Women

Ghaziabad, [email protected], [email protected]

[email protected], [email protected]

Abstract — Teleportation also called, as Quantum

Teleportation is a technique, which involves the

duplication or re-creation of physical properties using

light beams. Teleportation involves the transfer of“quantum States” between two separate atoms. It relies

on a strange behaviour that exists at the atomic scale

known as "entanglement", whereby two particles can have

related properties even when they are far apart.

Entanglement allows particles to have a much closer

relationship than is possible in classical physics. If twoparticles are entangled, we can know the state of one

particle by measuring the state of the other. For

example, two particles can be entangled such that the

spin of one particle is always "up" when the spin of

the other is "down", and vice versa. An additional

feature of quantum mechanics is that the particle can

exist in a superposition of both these states at the

same time. The landmark experiments are being

viewed as a major advance in the quest to achieve

ultra-fast computers, inside which teleportation could

provide a form of invisible "quantum wiring". Thesemachines would be able to handle far bigger andmore complex loads than today's super-computers, and at

many times their speed.

Here in this report, we are going to discuss about the

technique involved in quantum computing, quantum

cryptography and quantum teleportation and in specific

Quantum Computers along with its advantages and

disadvantages. Moreover, the future aspects of quantum

teleportation such as human teleportation have also been

overviewed.

Keywords –

I. INTRODUCTION

This is the dream of teleportation- the ability to travelfrom place to place without having to pass through thetedious intervening miles accompanied by a physical

vehicle and airline-food rations. Although the teleportationof large objects or humans is still remains a fantasy, quantumteleportation has become a laboratory reality for photons,the individual particles of light. Quantum teleportationexploits some of the most basic features of quantummechanics, a branch of physics invented in the first quarterof the 20th century to explain processes that occur at the

level of individual atoms. From the beginning, theoristsrealized that quantum physics led to a plethora of new

phenomena, some of which defy common sense.Technological progress in the final quarter of the 20th century has enabled researchers to conduct many experimentsthat not only demonstrate fundamental, sometimes bizarreaspects of quantum mechanics but, as in the case ofquantum teleportation, apply them to achieve previouslyinconceivable feats.

II. QUANTUM TELEPORTATION

Quantum teleportation, or entanglement-assistedteleportation, is a process by which a qubit (the basic unitof quantum information) can be transmitted exactly (in

principle) from one location to another, without the qubit being transmitted through the intervening space. It is usefulfor quantum communication and computation. It does nottransport the system itself, nor does it allow communicationof information at superluminal speed. Neither does it

concern rearranging the particles of a macroscopic objectto copy the form of another object.

Figure 1: Representation of Quantum Teleportation

In quantum teleportation the original object is scanned insuch a way as to extract all the information from it, thenthis information is transmitted to the receiving location andused to construct the replica, not necessarily from the actual

2012 Second International Conference on Advanced Computing & Communication Technologies

978-0-7695-4640-7/12 $26.00 © 2012 IEEE

DOI 10.1109/ACCT.2012.23

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2012 Second International Conference on Advanced Computing & Communication Technologies

978-0-7695-4640-7/12 $26.00 © 2012 IEEE

DOI 10.1109/ACCT.2012.23

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material of the original, but perhaps from atoms of the samekinds, arranged in exactly the same pattern as the original.

A. Quantum

In physics, a quantum is the minimum amount of any physical entity involved in an interaction. Behind this, one

finds the fundamental notion that a physical property may be "quantized," referred to as "the hypothesis of

quantization". This means that the magnitude can take ononly certain discrete values. There is a related term ofquantum number . An example of an entity that is quantized isthe energy transfer of elementary particles ofmatter (called fermions) and of photons and other bosons.

Figure 2: Photon Representation

A photon is a single quantum of light, and is referred toas a "light quantum". The energy of an electron bound to

an atom (at rest) is said to be quantized, which results inthe stability of atoms, and of matter in general.

As incorporated into the theory of quantum mechanics,this is regarded by physicists as part of the fundamentalframework for understanding and describing nature at theinfinitesimal level.

Normally quanta are considered to be discrete packets withenergy stored in them. Max Planck considered these quantato be particles that can change their form (meaning thatthey can be absorbed and released). This phenomenon can

be observed in the case of black body radiation, when itis being heated and cooled.

The word "quantum" comes from the Latin "quantus," for"how much." "Quanta" meaning short for "quanta ofelectricity" (or electron) was used in a 1902 article on the

photoelectric effect by Philipp Lenard, who creditedHermann von Helmholtz for using the word in the areaof electricity. However, the word quantum in general waswell known before 1900. It was often used by physicians,such as the term quantum satis. Both Helmholtz and Juliusvon Mayer were physicians as well as physicists.

Helmholtz used quantum with reference to heat in hisarticle on Mayer's work, and indeed, the word quantumcan be found in the formulation of the first law ofthermodynamics by Mayer in his letter dated July 24, 1841.Max Planck used "quanta" to mean "quanta of matter andelectricity", gas, and heat. In 1905, in response to Planck'swork and the experimental work of Lenard, who explained

his results by using the term "quanta of electricity", AlbertEinstein suggested that radiation existed in spatiallylocalized packets which he called "quanta oflight" ("Lichtquanta").

The concept of quantization of radiation was discovered in1900 by Max Planck, who had been trying to understandthe emission of radiation from heated objects, known as

black body radiation. By assuming that energy can only beabsorbed or released in tiny, differential, discrete packets hecalled "bundles" or "energy elements,", Planck accounted forthe fact that certain objects change colour whenheated. On December 14, 1900, Planck reported hisrevolutionary findings to the German Physical Society and

introduced the idea of quantization for the first time as a part of his research on black body radiation. As a resultof his experiments, Planck deduced the numerical value ofh, known as the Planck constant, and could also report a

more precise value for the Avogadro-Loschmidt number,the number of real molecules in a mole and the unit ofelectrical charge, to the German Physical Society. Afterhis theory was validated, Planck was awarded the NobelPrize in Physics in 1918 for his discovery.

B. Teleportation

Teleportation is the name given by science fiction writersto the feat of making an object or person disintegrate in

one place while a perfect replica appears somewhere else.How this is accomplished is usually not explained indetail, but the general idea seems to be that the originalobject is scanned in such a way as to extract all theinformation from it, then this information is transmitted tothe receiving location and used to construct the replica, notnecessarily from the actual material of the original, but

perhaps from atoms of the same kinds, arranged in exactlythe same pattern as the original. A teleportation machinewould be like a fax machine, except that it would workon 3-dimensional objects as well as documents, it would

produce an exact copy rather than an approximatefacsimile, and it would destroy the original in the processof scanning it. A few science fiction writers consider

teleporters that preserve the original, and the plot getscomplicated when the original and teleported versions ofthe same person meet; but the more common kind ofteleporter destroys the original, functioning as a supertransportation device, not as a perfect replicator of soulsand bodies.

Teleportation involves dematerializing an object at one point, and sending the details of that object's precise atomic

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configuration to another location, where it will bereconstructed.What this means is that time and space could beeliminated from travel-we could be transported to anylocation instantly, without actually crossing a physicaldistance.

Figure 3: Quantum Teleportation Method

III. PREREQUISITES

The prerequisites for quantum teleportation are a qubitthat is to be teleported, a conventional communicationchannel capable of transmitting two classical bits (i.e., oneof four states), and means of generating an entangled EPR pair of qubits, performing a Bell measurement on

the EPR pair, and manipulating the quantum state of oneof the pair. The protocol is then as follows:

An EPR pair is generated and distributed to twoseparate locations, A and B.

At location A, a Bell measurement of the EPR pair qubit and the qubit to be teleported (for

example, quantum state of a photon) is performed, yielding two classical bits ofinformation. Both qubits are destroyed.

Using the classical channel, the two bits are sentfrom A to B. (This is the only potentially time-consuming step, due to speed-of-lightconsiderations.)

At location B, the EPR pair qubit is modified (ifnecessary), using the two bits to select the

correct one of four possible quantum states. Aqubit identical to that chosen for teleportation (for

example, quantum state of a photon) results.

Figure 4: Diagram for quantum teleportation of photon

IV. TERMINOLOGY RELATED TO QUANTUM

TELEPORTATION

A. QUBIT

In quantum computing, a qubit or quantum bit is aunit of quantum information — the quantum analogue of theclassical bit — with additional dimensions associated to thequantum properties of a physical atom. The physicalconstruction of a quantum computer is itself anarrangement entangled atoms, and the qubit represents boththe state memory and the state of entanglement in asystem. A quantum computation is performed by initializinga system of qubits with a quantum algorithm —

"initialization" here referring to some advanced physical process that puts the system into an entangled state.

The qubit is described by a quantum state in a two-state quantum-mechanical system, which is formallyequivalent to a two-dimensional vector space over thecomplex numbers. One example of a two-state quantumsystem is the polarization of a single photon: here the twostates are vertical polarisation and horizontal polarisation.In a classical system, a bit would have to be in one stateor the other, but quantum mechanics allows the qubit to bein a superposition of both states at the same time, a

property which is fundamental to quantum computing.

Figure : Basic Information of Qubit

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Figure 5: Qubit

B. EPR EFFECT

The EPR paradox (or Einstein – Podolsky – Rosen paradox) isa topic in quantum physics and the philosophy of scienceconcerning the measurement and description of

microscopic systems by the methods of quantum physics. Itrefers to the dichotomy that either the measurement of a physical quantity in one system must affect themeasurement of a physical quantity in another, spatiallyseparate, system or the description of reality given by awave function must be incomplete.

This challenge to the Copenhagen interpretation of quantum physics that only the position or momentum of a particle, butnot both, can be known with certainty was originated from theconsequences of a thought experiment in 1935 byEinstein, Podolsky and Rosen. The paper they authored

indicated what seemed to be a flaw in the interpretation.The experiment involved two systems that initially interact

with each other and are then separated. Then the position ormomentum of one of the systems is measured, and due tothe known relationship between the (measured) value of thefirst particle and the value of the second particle, theobserver is aware of that value in the second particle. Ameasurement of the other value is then made on the second

particle, and, once again, due to the relationship betweenthe two particles, that value is then known in the first particle.This outcome seems to violate the uncertainty principle, as

both the position and momentum of a single particle would be known with certainity.

Figure 6: EPR pair

C. QUANTUM ENTANGLEMENT

Quantum entanglement is a property of the state of aquantum mechanical system containing two or moredegrees of freedom, whereby the degrees of freedom that

make up the system are linked in such a way that thequantum state of any of them cannot be adequatelydescribed independently of the others, even if theindividual degrees of freedom belong to different objectsand are spatially separated. Peculiar non classical

correlations can be observed in such systems

Entanglement can be measured, transformed, purified, andteleported. A quantum system in an entangled state can beused as a quantum information channel to perform tasksthat are impossible for classical systems, and is alsorequired to achieve the exponential speed up of quantumcomputation.

Figure 7: photon quantum entanglement

V. APPLICATIONS OF QUANTUM

TELEPORTATION

A. Quantum Computer

A quantum computer is a device for computation thatmakes direct use of quantum mechanical phenomena, suchas superposition and entanglement, to perform operations ondata. Quantum computers are different from traditionalcomputers based on transistors. The basic principle behindquantum computation is that quantum properties can beused to represent data and perform operations on thesedata. A theoretical model is the quantum Turing machine,also known as the universal quantum computer.

Figure 8: Quantum Computer Chip

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B. Quantum Cryptography

Until modern times, cryptography referred almostexclusively to encryption, which is the process of convertingordinary information into unintelligible gibberish. Decryption is the reverse, in other words, moving from theunintelligible cipher text back to plaintext.

Figure 9:

VI. FUTURE ASPECTS OF QUANTUM

TELEPORTATION

HUMAN TELEPORTATION

For a person to be transported, a machine would have to be built that can pinpoint and analyse all of the 10 tothe power 28 atoms that make up the human body. That'sa more than a trillion atoms. This machine would thenhave to send this information to another location, wherethe person's body would be reconstructed with exact

precision. Molecules couldn't be even a millimetre out of place, lest the person arrive with some severe neurologicalor physiological defect.

Figure 10: Human Teleportation

Teleportation would combine genetic cloning withdigitization. In this biodigital cloning, tele-travelers wouldhave to die, in a sense. Their original mind and bodywould no longer exist. Instead, their atomic structure would

be recreated in another location, and digitization would

recreate the travelers' memories, emotions, hopes anddreams. So,the travellers s would still exist, but they woulddo so in a new body, of the same atomic structure asthe original body, programmed with the same information.

VII.

ADVANTAGES AND DISADVANTAGEA. Advantages

Teleportation Technology is now being used byorganizations across the world to enable people to bein two (or more) places at once. These organizationshave recognized the substantial communication

benefits of the technology.

Genuine eye-to-eye contact with individuals oraudiences in the distant location, which means we canmake that personal connection count wherever we are.The quality of the communication means that we areable to see and respond to the mood and bodylanguage of the person to whom we are speaking

to, to build trust and understanding.

There is a natural two-way communication with noaudio interference or discernable latency even if thecommunication is across twelve time zones.

The financial benefits are significant too. Substantialsavings in travel and accommodation costs.

B. Disadvantages

Quantum mechanics makes the application muchmore fragile against noise.

While doing human teleportation in future, the personmay arrive with some severe neurological or

physiological defect.

Figure 11: Disadvantge of Human Teleportation

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VIII. CONCLUSION

Quantum teleportation is a direct descendant of thescenarios debated by Einstein and Bohr. It doessomething very unique in the annals of science. It showsthat it is possible for one thing to effect another withoutany intervening mechanism involved.

This has been the one gauntlet that has always beentossed by scientists towards believers in things like psychism, magic, miracles, astrology, etc. But like alltechnologies, scientists are sure to continue to improve uponthe ideas of teleportation, to the point that we may oneday be able to avoid such harsh methods.Teleportation technology is fast becoming an integral part ofthe future. The researchers and scientists makes it clear thatthe teleportation technology "opens the way for innovationand new ways of teaching and learning".

REFERENCES

[1]. http://www.zamandayolculuk.com/cetinbal/QUANTUMTELEPORT

[2]. http://www.research.ibm.com/quantuminfo/teleportation/

[3]. http://technovate.org/web/articles/quantumthought.html

[4]. http://www.seminarprojects.com/Thread-quantum-teleportation

[5]. http://qso.lanl.gov/qc/ [6]. http://ewh.ieee.org/r10/bombay/news4/Quantum_Co

mputers.htm [7].

http://arstechnica.com/science/news/2010/12/quantum-teleportation-finds-a-place-in-quantum-computers.ars

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an investigation of quantum teleportation

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