PROJECT-1
Quantum Information Science (QIS)
Quantum Entanglement and Quantum Network (QuNET)
Telecom QuNET
Embedded Files
PROJECT-1
Project Title: Experimental Demonstration of Entanglement based Atom-Photon
Quantum Network (AP-QuNET) using Entangled Photons at Telecom Wavelength ^
Key Words: Quantum Information Science (QIS), Quantum Artificial Intelligence (QAI), Quantum Engineering, Quantum Communication, Quantum Entanglement, Quantum Teleportation, Entanglement Swapping, Quantum Photonic Interconnections (QuIC), Atom-Photon Quantum Network, Quantum Internet.
Overview of this Project
Quantum Superposition and Quantum Entanglement (Greenberger, Horne, & Zeilinger, Phys. Today 46 (8), 22 (Aug. 1993); R. Horodecki et al., Rev. Mod. Phys. 81, 865 (2009)) are bed rocks on which current paradigm of quantum information is resting. Superposition and entanglement are playing pivotal role for building next generation of quantum information technology (QIT) such as quantum computer and quantum internet. Quantum computer is a next generation of computing machine, which is exponentially faster than present-day classical digital computers. Quantum internet is a next generation of computer internet, which has exponentially larger state-space that allow much more efficient & secure information transfer then present-day classical computer internet.
This research project is based on quantum entanglement (Click For: Quantum Entanglement ) and its applications to development of next generation of atom-photon quantum network (AP-QuNET). Entanglement is at the heart of quantum mechanics and is central to the entire paradigm of quantum information science (QIS). Entanglement was the subject of recent Physics Nobel Prize (Click: Nobel-Prize-2022/). This Physics Nobel Prize was awarded for pioneering quantum information science experiments using entangled photons. Therefore, entanglement is currently a very hot topic of research. Development of artificial intelligence (AI) systems such as neural network, using principles of physics, was the subject of recent Physics Nobel Prize (Click: Physics-Nobel-Prize-2024). Atom-photon quantum network, like neural network, is also an artificial intelligence (AI) system. Therefore, development of atom-photon quantum network using techniques of atomic physics, entanglement, and photons is a subject of very intense research in quantum physics, quantum optics, quantum information science (QIS), and artificial intelligenc
This research project is continuation of my past research on Quantum Information Science (QIS)/ Quantum Communication using two-qubit EPR (Einstein-Podolsky-Rosen) Bell states. Summary of this past research is available in a Pdf file, which can be downloaded. To download this Pdf file cllck on Page: PAST, which is located on TOP-ROW of this website and download Pdf file: C-QED.
My current research work is on multi-qubit entanglement (Click: Multipartite Entanglement) in Graph States ((M. Hein, J. Eisert, & H. J. Briegel, Phys. Rev. A 69, 062311 (2004), Download: Graph-State Pdf ) and its applications to multi-qubit quantum teleportation/ multi-qubit entanglement swapping/ multi-party quantum communication experiments, which leads to development of Quantum network (Click: Quantum Network). Entanglement in multi-qubit states is more complicated than in two-qubit entanglement. Multi-qubit quantum entangled states used in this project are Greenberger-Horne-Zeilinger (GHZ) State (Click: GHZ), Cluster State (Click: CLUSTER), Brown State ( I. D. K. Brown et al., J. Phys. A 38 (5), 1119-1131 (2005)) (Download: BROWN Pdf) and Borras State (A. Borras et al., J. Phys. A 40 (44), 13407-13421 (2007)) (Download: BORRAS Pdf), Such multi-qubit entangled states have bizarre quantum properties, which are not observed in two-qubit entanglement. Theoretically, the subject of multi-qubit entanglement is very poorly understood, and experimentally very little work has been done on multi-qubit entanglement. Further, multi-qubit entanglement give rise to striking contradiction with local realism for non statistical prediction of quantum mechanics. Multi-qubit entangled states can be synthesized in single cold atoms in high-finesse Fabry-Perot cavities, in cold atoms in the optical lattice, in atomic ions in the ion trap, and in entangled photons generated by spontaneous parametric down conversion (SPDC) in nonlinear solid-state crystals. Multi-qubit entangled states are used to test foundation of quantum mechanics and to improve detection sensitivity and precision of measurement in atomic and molecular spectroscopy (Toward Heisenberg-Limited Spectroscopy with Multiparticle Entangled States, D. J. Wineland et al., Science 304, 1476 (2004): Download: Wineland Pdf). Two-qubit EPR Bell-states can be used to estabkish quantum interconnection only between two nodes of a quantum network. Therefore, commonly used EPR Bell-states are NOT SUITABLE for designing multi-node (more than two nodes) quantum network. However, nodes of a multi-node quantum network can be quantum mechanically interconnected with multi-qubit entangled states. Therefore, multi-qubit states are used to establish quantum interconnections (QuICs) (D. Awschalom et al., PRX Quantum 2, 017002 (2021); J. Wang et al., Optica 3 (4), 407 (2016)) among nodes of a multi-node quantum network and among different units of a quantum computer. Thus, multi-qubit entangled states are essential for building the next generation of quantum information technology (QIT), such as modular quantum computers & global scale quantum internet.
In this atom-photon quantum network / photonic quantum network project, nodes of the network are represented by Raman quantum memories, which are designed using hyperfine levels in the neutral Cesium (Cs) atoms and multi-photon quantum entangled states are generated by nonlinear optical technique of chirped-pulse (Physics Nobel Prize Click: (Nobel-Prize-2018)) spontaneous parametric down-conversion (SPDC) of ultrafast (/femtosecond) optical pulses in group velocity matched (GVM) (quasi-phase matched (QPM) solid-state nonlinear optical crystals. These entangled states are generated at the telecom wavelength 1584 nm. Genuine entanglement in the generated multi-photon entangled states is detected with witness operator. These laboratories generated multi-photon entangled states are then distributed through optical fibers to remotely located nodes of a quantum network. Due to entanglement among the distributed photons, nodes get quantum mechanically interconnected. We then conduct multi-party quantum teleportation experiments, which are useful for understanding communication of quantum information both within quantum computers & among nodes of a quantum networks. My recent published research (Elementary Tripartite Quantum Communication Photonic Network at the Telecom Wavelength, P. S. Bhatia, Laser Physics 31 (9), 095203 (2021)) shows that in multi-party teleportation, unlike in two-party (Alice and Bob) teleportation (C. H. Bennett et al., Phys. Rev. Lett. 70, 1895 (1993)), qubit to be teleported is first split into fragments and then at the destination station original qubit is reconstructed from the fragments. This published research also shows that for development of quantum network, teleportation alone is not sufficient, but development of quantum network imposes additional requirements. One such requirement is the separability property of quantum channel, which is used to interconnect different nodes of the network. Another such requirement is the quantum error correction (QEC) within the network. My recent published research ((Long-Distance Multi-Party Quantum Teleportation for Quantum Networking Using Multi-Qubit Entanglement Swapping, P. S. Bhatia, Phys. Rev. X Quantum)) also shows that with technique of multi-qubit entanglement swapping, two (or more) fully separated quantum networks with smaller number of nodes can be merged to design a quantum network with larger number of nodes. For terminology used in this project click on Page: PHOTONICS, which is located on TOP-ROW of this website.
This is a large-scale and very sophisticated atom-photon experiment, which uses special purpose high- repetition-rate ultrafast (femtosecond) lasers & the latest and the most advanced quantum information technology such as superconducting nanowire photon number resolving (PNR) single photon detectors (SNSPD) in the laboratory. For more information about lasers & amplifiers, nonlinear optical crystals, photodetectos, electronics, data acquisition, and data analysis required for this project click on Page: PHOTONICS, which is located on TOP-ROW of this website.
The ultimate goal of this project is to experimentally demonstrate a multi-node Atom-Photon Quantum Network, which is a very tough & hard experimental goal to achieve.
Research presented in this project is original and is significant contribution, with high potential impact, to very rapidly advancing field of quantum science and technology.
This research is important for the development of the next generation of quantum internet. Majority of other researchers, at different universities, are using two-qubit EPR Bell-states, which can lead to communication only between two nodes of a quantum network. This is the only major project in the whole United State, which employs multi-qubit entangled states that leads to communication among nodes of a multi-node quantum network. Therefore, this project represents US leadership in the field of quantum communication. Within the broad field of quantum information science (QIS) and artificial intelligence (AI), development of quantum internet has been declared as a high priority research area by National Science Foundation (NSF) and US Department of Energy (DOE). This research work is also very important for National Security and Military Intelligence.
Note: While reviewing this PROJECT-1, you will find helpful to review Related Page: PHOTONICS, which is located on TOP-ROW of this website.
Research Proposals and
Different Experiments Related to this Project
Different Experiments within this project are given below. For each of these experiments, there is a separate Research Proposal, which can be submitted to external federal funding agencies. These proposals are almost ready to be submitted. Brief information about these research proposals is available in a Pdf file, which can be downloaded. To download this Pdf file click on the link below.
Download: PROPOSAL-(QIS) Pdf
Experiment # 1
Title: Experimental Demonstration of High Bandwidth and High-Speed Cold Atom Cesium (Cs) Quantum Memory.
Aim of this experiment is to demonstrate high-bandwidth and high-speed Raman quantum memory, in which photonic qubit can be read into and retrieved from the memory by application of write and read optical pulses. In this memory photonic qubit is stored as Raman excitation in the ground state of the hyperfine level of Cesium (Cs) atom. Storage time of this memory is limited by Doppler Broadening in the Cesium atoms and this storage time can be increased by laser cooling the atoms in a Magneto-Optical Trap (MOT).
Experiment # 2
Title: Experimental Interfacing of Atom-Photon Entanglement with Telecom Quantum Network using Quantum Frequency Conversion (QFC).
Aim of this experiment is to demonstrate Quantum Frequency Converter (QFC), which can interconvert photonic qubit between Cesium (Cs) atom quantum memory operating at wavelength 895 nm and quantum network operating at telecom wavelength 1584 nm, while preserving quantum state of the photon. This frequency converter is based on second-order nonlinear susceptibility of Lithium Niobate crystal, which is used in the converter. This frequency converter operates at single photon level. Single photon level operation of this frequency converter is achieved by following techniques: use of nonlinear crystal with greater magnitude of second-order nonlinear susceptibility, use of waveguide, Quasi-Phase Matching (QPM), injecting seed pulse in the crystal, cascaded nonlinearity, and by introducing EIT (Electromagnetically Induced Transparency) in the crystal.
Experiment # 3
Title: Enhancement of Photon Flux of Entangled Photon Sources based on Ultrafast Spontaneous Parametric Down-Conversion (SPDC) in Nonlinear Crystals
In quantum communication laboratories, entangled photons are generated by Spontaneous Parametric Down-Conversion (SPDC) of pump photons in solid-state nonlinear crystals. Due to weak magnitude of nonlinear susceptibility of crystal & probabilistic nature of down-conversion, flux of generated entangled photons is extremely poor. This is one of the major stumbling blocks for developing global scale quantum internet. Aim of this experiment is to increase flux of entangled photons by following techniques: Quasi-Phase Matched (QPM), Group Velocity Matched (GVM), chirping the width of pump pulse, use of cascaded nonlinearity, use of high-efficiency detectors, use of quantum heterodyning, and injection seeding the nonlinear crystal.
Experiment # 4
Title: Experimental Demonstration of High-Flux Entangled Photon Sources for Generation & Detection of Genuinely Entangled Multi-Photon State.
Aim of this experiment is to develop high flux entangled photon sources at telecom wavelength, for experimental generation of following multi-photon quantum entangled states: Three-Qubit GHZ, Six-Qubit GHZ, Four-Qubit Cluster, Six-Qubit Cluster, Five-Qubit Brown, and Six-Qubit Borras states. These multi-qubit entangled states will be generated by fusion, which is a technique in which entangled states of smaller number of qubits are fused together to synthesize entangled state of larger number of qubits. Fusion is experimentally achieved with polarizing beam splitter cubes (PBS), photon number resolving (PNR) detectors, and multi-fold coincidence counting electronics. Genuine entanglement in the generated multi-qubit entangled states is detected by measuring expectation value of witness operator for the entangled state.
Experiment # 5
Title: Demonstration of Multi-Node Quantum Communication Photonic Network Using Entangled Photons at Telecom Wavelength.
Aim of this experiment is to demonstrate Three-Node, Four-Node, Five-Node, Six-Node, and Ten-Node ideal quantum networks, in which a photonic qubit can be teleported from any node to any other node of the network. For demonstration of Three-Node/ Four-Node/ Five-Node/ Six-Node quantum network, Three/ Four/ Five/ Six nodes of the network will be respectively interconnected with Three-Qubit GHZ/ Four-Qubit Cluster/ Five-Qubit Brown/ Six-Qubit Cluster or Six-Qubit Borras state. Ten-Node quantum networks will be demonstrated by merging two Six-Node quantum networks with technique of multi-qubit entanglement swapping.
Brief Description of this Project
Short version of the description of this project (PROJECT-1) can be found in a Pdf file with name: PROJECT-1-(QIS), which can be downloaded. To download this file click on the link below. Complete version of this project is available on request.
Download: Project-1-(QIS) Pdf
Publications Related to this Project
My selected current publications, directly related to this proposed project, are given below. Just clicking on these publications is sufficient. Note majority of my publications are single authored / first authored and further these publications are very detailed.
[1] Elementary Tripartite Quantum Communication Photonic Network
at the Telecom Wavelength, P. S. Bhatia, Laser Physics 31 (9), 095203 (2021).
Download: (A-PUB-QIS) Pdf
[2] Experimental Tripartite Quantum State Sharing and Perfect Teleportation of the Two-Qubit
Photonic State using Genuinely Entangled Multipartite States,
P. S. Bhatia, J. Opt. Soc. Am. B 31, 154- 163 (2014).
Download: (B-PUB-QIS) Pdf
[3] Quantum Information Splitting and Open-Destination Teleportation Using
Decomposable Multipartite Quantum Channel: Part I : Theory,
P. S. Bhatia, J. Opt. Soc. Am. B 31, 972-979 (2014).
Download: (C-PUB-QIS) Pdf
[4] Quantum Information Splitting and Open-Destination Teleportation Using Decomposable
Multipartite Quantum Channel: Part II: Experimental,
P. S. Bhatia, J. Opt. Soc. Am. B 31, 1255-1262 (2014).
Download: (D-PUB-QIS) Pdf
[5] Dense Quantum Communication using Single- and Two-Particle Operations on
Six-Particle Cluster State, P. S. Bhatia, Quant. Inf. and Comp (QIC) Vol. 16, No 3 & 4, 0271-0290 (2016).
Download: (E-PUB-QIS) Pdf
Presentation Related to this Project
Presentation on this Project, which has selected view graphs, is available in a Pdf file, which can be downloaded. To download this Pdf file click on the link below.
Download: (VG-Project-1) Pdf
Nobel Prize Associated with this Project
Year: 2022
Pioneering Quantum Information Science Experiments using
Entangled Photons.
(1) Violation of Bell Inequalities,
(2) Quantum Teleportation,
(3) Entanglement Swapping.
Alain Aspect, John F. Clauser, and Antone Zeilinger
Click: Nobel-Prize-2022/.
General Readings Related to this Project
(1) Multiparticle Interferometry and Superposition Principle,
D. M. Greenberger, M. A. Horne, and A. Zeilinger, Phys. Today 46 (8), 22 (1993).
DOWNLOAD: (READ-1) Pdf
(2) Quantum information and Computation,
C. H. Bennett, Phys. Today 48 (10), 24 (1995).
DOWNLOAD: (READ-2) Pdf
(3) Quantum Teleportation,
A. Zeilinger, Scientific American pp. 50, April (2000).
(4) Quantum Networking, (2025)
By Richard O. O.
Click: Read Now
(5) Quantum Internet, H. J. Kimble, Nature 453, 1023 (2008).
DOWNLOAD: (READ-5) Pdf
(6) Multiphoton Entanglement and Interferometry,
A. Zeilinger et al., Rev. Mod. Phys. 84, 777 (2012).
DOWNLOAD: (READ-6) Pdf
Textbooks Related to this Project
Quantum Computing
Quantum Computing: A Short Course from Theory to Experiment
Joachim Stolze and Dieter Suter
Wiley-VCH-(2008)
Quantum Communication
Quantum Teleportation and Entanglement
A. Furusawa and P. van Loock
Wiley-VCH-(2011).
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