Teleporting Grin of a Quantum Chesire Cat without cat

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1998

Quantum teleportation-the transmission and reconstruction over arbitrary distances of the state of a quantum system-is demonstrated experimentally. During teleportation, an initial photon which carries the polarization that is to be transferred and one of a pair of entangled photons are subjected to a measurement such that the second photon of the entangled pair acquires the polarization of the initial photon. This latter photon can be arbitrarily far away from the initial one. Quantum teleportation will be a critical ingredient for quantum computation networks.

Alhun Aydın, 2010

Teleportation is usually seen as a science-fiction term. In spite of that, the possibility of teleportation within the range of physics laws, has been being studied since its discovery in 1993. We examine the teleportation that is done with using quantum entanglement, and we explore quantum teleportation both theoretically and experimentally, with also giving fundamental background knowledge of the process. Furthermore we discuss the philosophy of some weird quantum phenomena with regard to quantum teleportation.

Physical Review A, 2000

We study the experimental realisation of quantum teleportation as performed by Bouwmeester et al. [Nature 390, 575 (1997)] and the adjustments to it suggested by Braunstein and Kimble [Nature 394, 841 (1998)]. These suggestions include the employment of a detector cascade and a relative slow-down of one of the two down-converters. We show that coincidences between photonpairs from parametric down-conversion automatically probe the non-Poissonian structure of these sources. Furthermore, we find that detector cascading is of limited use, and that modifying the relative strengths of the down-conversion efficiencies will increase the time of the experiment to the order of weeks. Our analysis therefore points to the benefits of single-photon detectors in non-postselected type experiments, a technology currently requiring roughly 6 • K operating conditions. PACS number(s): 03.67.*, 42.50.Dv Quantum entanglement, an aspect of quantum theory already recognised in the early days, clearly sets quantum mechanics apart from classical mechanics. More recently, fundamentally new phenomena involving entanglement such as cryptography, error correction and dense coding have been discovered . In particular, the field has witnessed major steps forward with the experimental realisation of quantum teleportation [4-9].

In this paper I have investigated what quantum teleportation is and its implications in the creation of the quantum internet. The paper begins with a broad description of quantum mechanics and the fascinating concepts of superposition of states and quantum entanglement, and how they are fundamental to quantum teleportation. Quantum teleportation is an intriguing consequence of quantum entanglement and superposition states of qubits. It is the technique of transmitting one qubit's state to another qubit, at a completely different location, without physically transporting the qubit. Taking the classic example of Alice and Bob the whole procedure of quantum teleportation is explained. The paper also focuses on the possibility of a quantum internet using the concepts of quantum teleportation and quantum repeaters.It states the advantages of the quantum internet and why it would be a huge leap for mankind. The paper also mentions the use of quantum teleportation to improve quantum cryptography for safer transactions. The conclusions of the paper focus mainly on the hurdles of the creation of the quantum internet such as the decoherence effect.

2003

Recent experiments confirm that quantum teleportation is possible at least for states of photons and nuclear spins. The quantum teleportation is not only a curious effect but a fundamental protocol of quantum communication and quantum computing. The principles of the quantum teleportation and the entanglement swapping are explained, and physical realizations of teleportation of optical and atomic states are discussed.

Scientific Reports, 2014

A simplified version of quantum teleportation protocol is presented here. Its experimental confirmation will have deep implications for a better understanding of quantum entanglement with a particular projection on quantum communications.

Nature Physics, 2006

Q uantum teleportation 1 , a way to transfer the state of a quantum system from one location to another, is central to quantum communication 2 and plays an important role in a number of quantum computation protocols 3-5 . Previous experimental demonstrations have been implemented with single photonic 6-11 or ionic qubits 12,13 . However, teleportation of single qubits is insufficient for a large-scale realization of quantum communication and computation 2-5 . Here, we present the experimental realization of quantum teleportation of a twoqubit composite system. In the experiment, we develop and exploit a six-photon interferometer to teleport an arbitrary polarization state of two photons. The observed teleportation fidelities for different initial states are all well beyond the state estimation limit of 0.40 for a two-qubit system 14 . Not only does our six-photon interferometer provide an important step towards teleportation of a complex system, it will also enable future experimental investigations on a number of fundamental quantum communication and computation protocols 3,15-18 .

Nature, 2006

Quantum teleportation 1 is an important ingredient in distributed quantum networks 2 , and can also serve as an elementary operation in quantum computers 3 . Teleportation was first demonstrated as a transfer of a quantum state of light onto another light beam 4-6 ; later developments used optical relays 7 and demonstrated entanglement swapping for continuous variables 8 . The teleportation of a quantum state between two single material particles (trapped ions) has now also been achieved 9,10 . Here we demonstrate teleportation between objects of a different nature-light and matter, which respectively represent 'flying' and 'stationary' media. A quantum state encoded in a light pulse is teleported onto a macroscopic object (an atomic ensemble containing 10 12 caesium atoms). Deterministic teleportation is achieved for sets of coherent states with mean photon number (n) up to a few hundred. The fidelities are 0.58±0.02 for n=20 and 0.60±0.02 for n=5higher than any classical state transfer can possibly achieve 11 . Besides being of fundamental interest, teleportation using a macroscopic atomic ensemble is relevant for the practical implementation of a quantum repeater 2 . An important factor for the implementation of quantum networks is the teleportation distance between transmitter and receiver; this is 0.5 metres in the present experiment. As our experiment uses propagating light to achieve the entanglement of light and atoms required for teleportation, the present approach should be scalable to longer distances. Quantum teleportation-a disembodied transfer of a quantum state with the help of distributed entanglement-was proposed in a seminal paper 1 . The generic protocol of quantum teleportation begins with the creation of a pair of entangled objects which are shared by two parties, Alice and Bob. This step establishes a quantum link between them. Alice receives an object to be teleported and performs a joint measurement on this atomŝ 4 x x J J N = = , and the transverse projections with minimal quantum uncertainties, x z y J J J 2 1 2 2

Journal of Modern Optics, 2000

Quantum teleportation is one of the essential primitives of quantum communication. We suggest that any quantum teleportation scheme can be characterized by its efficiency, i.e. how often it succeeds to teleport, its fidelity, i.e. how well the input state is reproduced at the output, and by its insensitivity to cross talk, i.e. how well it rejects an input state that is not intended to teleport. We discuss these criteria for the two teleportation experiments of independent qubits which have been performed thus far. In the first experiment (Nature 390,575 (1997)) where the qubit states were various different polarization states of photons, the fidelity of teleportation was as high as 0.80 ± 0.05 thus clearly surpassing the limit of 2/3 which can, in principle, be obtained by a direct measurement on the qubit and classical communication. This high fidelity is confirmed in our second experiment (Phys. Rev. Lett. 80, 3891 (1998)), demonstrating entanglement swapping, that is, realizing the teleportation of a qubit which itself is still entangled to another one. This experiment is the only one up to date that demonstrates the teleportation of a genuine unknown quantum state.