Publications (77)
Classical State Detection Using Quantum State Tomography
Kim Fook Lee, Prem Kumar
We present a model to detect a classical state mixed with an idler photon from a polarization-entangled pair. A weak coherent light with a well-defined polarization, matched in wav…
Inverse-Designed Stretchable Metalens with Tunable Focal Distance
Francois Callewaert, Vesselin Velev, Shizhou Jiang +3
In this paper we present an inverse-designed 3D-printed all-dielectric stretchable millimeter wave metalens with a tunable focal distance. Computational inverse-design method is us…
Optical sum-frequency generation in whispering gallery mode resonators
Dmitry V. Strekalov, Abijith S. Kowligy, Yu-Ping Huang +1
We demonstrate sum-frequency generation in a nonlinear whispering gallery mode resonator between a telecom wavelength and the Rb D2 line, achieved through natural phase matching. D…
Quantum entanglement distribution coexisting with high-rate, broadband classical optical communications over a real-world fiber connecting remote, synchronized nodes
Gina M. Talcott, Ahnnika I. Hess, Laura d'Avossa +8
Compatibility with existing classical network infrastructure offers a scalable path towards deploying large-scale quantum networks. Here, we demonstrate O-band polarization-encoded…
Inverse designed broadband all-dielectric electromagnetic metadevices
Francois Callewaert, Vesselin Velev, Alan V. Sahakian +2
We present an all-dielectric metadevice platform realized by combining an inverse electromagnetic design computational method with additive manufacturing. As opposed to conventiona…
Illinois Express Quantum Network (IEQNET): Metropolitan-scale experimental quantum networking over deployed optical fiber
Joaquin Chung, Gregory Kanter, Nikolai Lauk +11
The Illinois Express Quantum Network (IEQNET) is a program to realize metro-scale quantum networking over deployed optical fiber using currently available technology. IEQNET consis…
Quantum Networks For Open Science
Thomas Ndousse-Fetter, Nicholas Peters, Warren Grice +9
The United States Department of Energy convened the Quantum Networks for Open Science (QNOS) Workshop in September 2018. The workshop was primarily focused on quantum networks opti…
All-optical switching of photonic entanglement
Matthew A. Hall, Joseph B. Altepeter, Prem Kumar
Future quantum optical networks will require the ability to route entangled photons at high speeds, with minimal loss and added in-band noise, and---most importantly---without dist…
Barbosa et al. Reply to ``Comment on 'Secure Communication using mesoscopic coherent states', Barbosa et al, Phys Rev Lett 90, 227901", Yuan and Shields, Phys. Rev. Lett. 94, 048901(2005)
Horace Yuen, Eric Corndorf, Geraldo Barbosa +1
Yuan and Shields claim that our data-encryption protocol is entirely equivalent to a classical stream cipher utilizing no quantum phenomena. Their claim is, indeed, false. Yuan and…
Accelerating Progress Towards Practical Quantum Advantage: The Quantum Technology Demonstration Project Roadmap
Paul Alsing, Phil Battle, Joshua C. Bienfang +32
Quantum information science and technology (QIST) is a critical and emerging technology with the potential for enormous world impact and is currently invested in by over 40 nations…
Heralding Single Photons Without Spectral Factorability
Yu-Ping Huang, Joseph B. Altepeter, Prem Kumar
Recent efforts to produce single photons via heralding have relied on creating spectrally factorable two-photon states in order to achieve both high purity and high production rate…
A quantum-mechanical study of optical regenerators based on nonlinear-loop mirrors
Giacomo M. D'Ariano, Prem Kumar
We present a quantum-mechanical analysis of a nonlinear interferometer that achieves optical switching via cross-phase modulation resulting from the Kerr effect. We show how it per…
Security of Y-00 and similar quantum cryptographic protocols
Horace P. Yuen, Prem Kumar, Eric Corndorf +1
It is claimed in Phys. Lett. A by T. Nishioka et. al. 327 (2004) 28-32, that the security of Y-00 is equivalent to that of a classical stream cipher. In this paper it is shown that…
Is orbital angular momentum always conserved in spontaneous parametric down-conversion?
Sheng Feng, Chao-Hsiang Chen, Geraldo A. Barbosa +1
In the non-linear optical process of type-II spontaneous parametric down-conversion, we present on an experiment showing that the two-photon detection amplitude of the down-convert…
Equivalence between the second order steady state for the spin-Boson model and its quantum mean force Gibbs state
Prem Kumar, K. P. Athulya, Sibasish Ghosh
When the coupling of a quantum system to its environment is non-negligible, its steady state is known to deviate from the textbook Gibbs state. The Bloch-Redfield quantum master eq…
Quantum Noise Randomized Ciphers
Ranjith Nair, Horace P. Yuen, Eric Corndorf +2
We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by…
Scalable Feedback Stabilization of Quantum Light Sources on a CMOS Chip
Danielius Kramnik, Imbert Wang, Anirudh Ramesh +8
Silicon photonics is a leading platform for realizing the vast numbers of physical qubits needed for useful quantum information processing because it leverages mature complementary…
Demonstration of a Quantum Controlled-NOT Gate in the Telecom Band
Jun Chen, Joseph B. Altepeter, Milja Medic +5
We present the first quantum controlled-NOT (CNOT) gate realized using a fiber-based indistinguishable photon-pair source in the 1.55 m telecommunications band. Using this free…
Optimal filtering and generation of entangled photons for quantum applications in the presence of noise
Jordan M. Thomas, Andrew R. Cameron, Akil Pathiranage +6
Filtering is commonly used in quantum optics to reject noise photons, and also to enable interference between independent photons. However, filtering the joint spectrum of photon p…
Quantum Networks Using Color Defects in Diamond: Principles, Progress, and Perspectives
Ayan Majumder, Cem Güney Torun, Tim Schröder +3
Large-scale quantum networks will enable entirely new applications of quantum information science in fields such as quantum communication, distributed quantum computing, sensing, a…
Picosecond Synchronization of Photon Pairs through a Fiber Link between Fermilab and Argonne National Laboratories
Keshav Kapoor, Si Xie, Joaquin Chung +20
We demonstrate a three-node quantum network for C-band photon pairs using 2 pairs of 59 km of deployed fiber between Fermi and Argonne National Laboratories. The C-band pairs are d…
Large Quantum imaging of nonlocal spatial correlations induced by orbital angular momentum
Adam R. Altman, Kahraman G. Köprülü, Eric Corndorf +2
Through scanned coincidence counting, we probe the quantum image produced by parametric down conversion with a pump beam carrying orbital angular momentum. Nonlocal spatial correla…
Quantum Wrapper Networking
S. J. Ben Yoo, Sandeep Kumar Singh, Mehmet Berkay On +4
We introduce a new concept of Quantum Wrapper Networking, which enables control, management, and operation of quantum networks that can co-exist with classical networks while keepi…
Hong-Ou-Mandel Interference with a Coexisting Clock using Transceivers for Synchronization over Deployed Fiber
Anirudh Ramesh, Daniel R. Reilly, Kim Fook Lee +8
Interference between independently generated photons is a key step towards distributing entanglement over long distances, but it requires synchronization between the distantly-loca…
Self-homodyne tomography of a twin-beam state
Giacomo M. D'Ariano, Michael Vasilyev, Prem Kumar
A self-homodyne detection scheme is proposed to perform two-mode tomography on a twin-beam state at the output of a nondegenerate optical parametric amplifier. This scheme has been…
Updating Quantum Cryptography Report ver. 1
Donna Dodson, Mikio Fujiwara, Philippe Grangier +24
Quantum cryptographic technology (QCT) is expected to be a fundamental technology for realizing long-term information security even against as-yet-unknown future technologies. More…
Asymptotic TCL4 Generator for the Spin-Boson Model: Analytical Derivation and Benchmarking
Prem Kumar, K. P. Athulya, Sibasish Ghosh
The spin-boson model is a widely used model for understanding the properties of a two-level open quantum system. Accurately describing its dynamics often requires going beyond the…
The conservation of orbital angular momentum and the two-photon detection amplitude in spontaneous parametric down-conversion
Sheng Feng, Chao-Hsiang Chen, Geraldo A. Barbosa +1
We study the two-photon detection amplitude of the down-converted beams in spontaneous parametric down-conversion when the physical variable of orbital angular momentum is involved…
On the security of AlphaEta: Response to `Some attacks on quantum-based cryptographic protocols'
Horace P. Yuen, Ranjith Nair, Eric Corndorf +2
Lo and Ko in [1] have developed some attacks on the cryptosystem called AlphaEta [2], claiming that these attacks undermine the security of AlphaEta for both direct encryption and…
Universal homodyne tomography with a single local oscillator
G. Mauro D'Ariano, Massimiliano F. Sacchi, Prem Kumar
We propose a general method for measuring an arbitrary observable of a multimode electromagnetic field using homodyne detection with a single local oscillator. In this method the l…
Designing Noise-Robust Quantum Networks Coexisting in the Classical Fiber Infrastructure
Jordan M. Thomas, Gregory S. Kanter, Prem Kumar
The scalability of quantum networking will benefit from quantum and classical communications coexisting in shared fibers, the main challenge being spontaneous Raman scattering nois…
Sustainable Quantum Computing: Opportunities and Challenges of Benchmarking Carbon in the Quantum Computing Lifecycle
Nivedita Arora, Prem Kumar
While researchers in both industry and academia are racing to build Quantum Computing (QC) platforms with viable performance and functionality, the environmental impacts of this en…
Quantum Theory of All-Optical Switching in Nonlinear Sagnac Interferometers
Yu-Ping Huang, Prem Kumar
Recently, our group has demonstrated an ultrafast, low-loss, fiber-loop switch based on a nonlinear Sagnac-interferometer design, using which entangled photons were shown to be rou…
Reply to: 'Reply to: "Comment on: `How much security does Y-00 protocol provide us?` " '
Ranjith Nair, Horace P. Yuen, Eric Corndorf +1
Nishioka et al claim in [1], elaborating on their earlier paper [2], that the direct encryption scheme called Y-00 [3,4] is equivalent to a classical non-random additive stream cip…
Experimental Demonstration of Software-Orchestrated Quantum Network Applications over a Campus-Scale Testbed
Md. Shariful Islam, Joaquin Chung, Ely Marcus Eastman +3
To fulfill their promise, quantum networks must transform from isolated testbeds into scalable infrastructures for distributed quantum applications. In this paper, we present a pro…
Experimental demonstration of interaction-free all-optical switching via the quantum Zeno effect
Kevin T. McCusker, Yu-Ping Huang, Abijith Kowligy +1
We experimentally demonstrate all-optical interaction-free switching using the quantum Zeno effect, achieving a high contrast of 35:1. The experimental data matches a zero-paramete…
Design and Implementation of the Illinois Express Quantum Metropolitan Area Network
Joaquin Chung, Ely M. Eastman, Gregory S. Kanter +12
The Illinois Express Quantum Network (IEQNET) is a program to realize metropolitan scale quantum networking over deployed optical fiber using currently available technology. IEQNET…
Ultrafast switching of photonic entanglement
Matthew A. Hall, Joseph B. Altepeter, Prem Kumar
To deploy and operate a quantum network which utilizes existing telecommunications infrastructure, it is necessary to be able to route entangled photons at high speeds, with minima…
Extrinsic orbital angular momentum of entangled photon-pairs in spontaneous parametric down-conversion
Sheng Feng, Prem Kumar
Starting from the standard Hamiltonian describing the optical non-linear process of spontaneous parametric down-conversion, we theoretically show that the generated entangled photo…
Distilling Quantum Entanglement via Mode-Matched Filtering
Yu-Ping Huang, Prem Kumar
We propose a new avenue towards distillation of quantum entanglement that is implemented by directly passing the entangled qubits through a mode-matched filter. This approach can b…
Quantum theory of degenerate two-photon state
Jun Chen, Kim Fook Lee, Prem Kumar
We developed a quantum theory for degenerate two-photon state generated from optical fiber, and compared the theory predictions with an experimental result which exhibit…
The effect of measurement uncertainties on the inferred stability of planes of satellite galaxies
Prem Kumar, Marcel S. Pawlowski, Kosuke Jamie Kanehisa +3
Observations have revealed that the MW, Andromeda, Centaurus A (and potentially other galaxies) host spatially thin and kinematically coherent planes of satellites. Such structures…
Non-Markovian Dynamics in Fiber Delay-line Buffers
Kim Fook Lee, Prem Kumar
We study the non-Markovian effect on a two-photon polarization entangled state, in which one photon from the pair is stored in a fiber delay-line buffer. We propose a model of a ph…
Antibunched Emission of Photon-Pairs via Quantum Zeno Blockade
Yu-Ping Huang, Prem Kumar
We propose a new methodology, namely "quantum Zeno blockade," for managing light scattering at a few-photon level in general nonlinear-optical media, such as crystals, fibers, sili…
Photonic Nonlinearities via Quantum Zeno Blockade
Yu-Zhu Sun, Yu-Ping Huang, Prem Kumar
Realizing optical-nonlinear effects at a single-photon level is a highly desirable but also extremely challenging task, because of both fundamental and practical difficulties. We p…
Self-stabilized Quantum Optical Fredkin Gate
Jonathan Hu, Yu-Ping Huang, Prem Kumar
Quantum optical Fredkin gate is an indispensable resource for networkable quantum applications. Its performance in practical implementations, however, is limited fundamentally by t…
Soliton Squeezing in a Mach-Zehnder Fiber Interferometer
Marco Fiorentino, Jay E. Sharping, Prem Kumar +2
A new scheme for generating amplitude squeezed light by means of soliton self-phase modulation is experimentally demonstrated. By injecting 180-fs pulses into an equivalent Mach-Ze…
An integrable optical-fiber source of polarization entangled photon-pairs in the telecom band
Xiaoying Li, Chuang Liang, Kim Fook Lee +3
We demonstrate an optical-fiber based source of polarization entangled photon-pairs with improved quality and efficiency, which has been integrated with off-the-shelf telecom compo…
Fiber Loop Quantum Buffer for Photonic Qubits
Kim Fook Lee, Gamze Gul, Zhao Jim +1
We report a fiber loop quantum buffer based on a low-loss 22 switch and a unit delay made of a fiber delay line. We characterize the device by using a two-photon polarizati…
Illinois Express Quantum Network for Distributing and Controlling Entanglement on Metro-Scale
Wenji Wu, Joaquin Chung, Gregory Kanter +12
We describe an implementation of a quantum network over installed fiber in the Chicago area.We present network topology and control architecture of this network and illustrate prel…
Erasing Quantum Distinguishability via Single-Mode Filtering
Monika Patel, Joseph B. Altepeter, Yu-Ping Huang +2
Erasing quantum-mechanical distinguishability is of fundamental interest and also of practical importance, particularly in subject areas related to quantum information processing.…
Polarization Tracking and Active Compensation Using Classical Headers in Quantum Wrapper Networking
Gamze Gül, James van Howe, Gregory S. Kanter +6
Quantum wrapper networking (QWN) is an emerging quantum networking protocol that wraps qubits in classical header bits to enable switching/routing, monitoring, and control without…
Quantum-noise--randomized data-encryption for WDM fiber-optic networks
Eric Corndorf, Chuang Liang, Gerg S. Kanter +2
We demonstrate high-rate randomized data-encryption through optical fibers using the inherent quantum-measurement noise of coherent states of light. Specifically, we demonstrate 65…
Cyber security of Mega Events: A Case Study of Securing the Digital Infrastructure for MahaKumbh 2025 -- A 45 days Mega Event of 600 Million Footfalls
Rohit Negi, Amit Negi, Manish Sharma +3
Mega events such as the Olympics, World Cup tournaments, G-20 Summit, religious events such as MahaKumbh are increasingly digitalized. From event ticketing, vendor booth or lodging…
Telecom-Band Entanglement Generation for Chipscale Quantum Processing
Kim Fook Lee, Prem Kumar, Jay E. Sharping +4
We demonstrate polarization-entanglement for non-degenerate and degenerate photon-pairs generated through Kerr-nonlinearity in a nano-scale silicon-on-insulator(SOI) waveguide. We…
Ultrastrong coupling limit to quantum mean force Gibbs state for anharmonic environment
Prem Kumar, Sibasish Ghosh
The equilibrium state of a quantum system can deviate from the Gibbs state if the system-environment (SE) coupling is not weak. An analytical expression for this mean force Gibbs s…
Optical-fiber source of polarization-entangled photon pairs in the 1550nm telecom band
Xiaoying Li, Paul L. Voss, Jay E. Sharping +1
We present a fiber based source of polarization-entangled photon pairs that is well suited for quantum communication applications in the 1550nm band of standard fiber-optic telecom…
Simulation of a Heterogeneous Quantum Network
Hayden Miller, Caitao Zhan, Michael Bishof +4
Quantum networks are expected to be heterogeneous systems, combining distinct qubit platforms, photon wavelengths, and device timescales to achieve scalable, multiuser connectivity…
Secure communication using coherent states
Geraldo A. Barbosa, Eric Corndorf, Prem Kumar +4
We demonstrate that secure communication using coherent states is possible. The optimal eavesdropping strategy for an M-ry ciphering scheme shows that the minimum probability of er…
QKD-Integrated Quantum Noise Stream Cipher: An Overview
Umesh Kumar Chandra, Avinash Kote, Neha Pathania +4
The paper reviews integrated quantum key distribution (QKD) and quantum noise stream cipher (QNSC) systems, explaining how QKD can continuously refresh the seed key for QNSC to ach…
Secure communication using mesoscopic coherent states
Geraldo A. Barbosa, Eric Corndorf, Prem Kumar +1
We demonstrate theoretically and experimentally that secure communication using intermediate-energy (mesoscopic) coherent states is possible. Our scheme is different from previous…
Functional Quantum Computing: An Optical Approach
Timothy Rambo, Joseph Altepeter, Giacomo Mauro D'Ariano +1
A new model of quantum computing has recently been proposed which, in analogy with a classical lambda-calculus, exploits quantum processes which operate on other quantum processes.…
Quantum computing hardware for HEP algorithms and sensing
M. Sohaib Alam, Sergey Belomestnykh, Nicholas Bornman +37
Quantum information science harnesses the principles of quantum mechanics to realize computational algorithms with complexities vastly intractable by current computer platforms. Ty…
Optimized Heralding Schemes for Single Photons
Yu-Ping Huang, Joseph B. Altepeter, Prem Kumar
A major obstacle to a practical, heralded source of single photons is the fundamental trade-off between high heralding efficiency and high production rate. To overcome this difficu…
Optimization of gain in traveling-wave optical parametric amplifiers by tuning the offset between pump- and signal-waist locations
Gideon Alon, Oo-Kaw Lim, Amar Bhagwat +4
We present experimental demonstration and modeling of the optimization of a phase-sensitive optical parametric amplifier by tuning the relative position between the pump- and signa…
Mode-resolved Photon Counting via Cascaded Quantum Frequency Conversion
Yu-Ping Huang, Prem Kumar
Resources for the manipulation and measurements of high-dimensional photonic signals are crucial for implementing quit-based applications. Here we propose potentially high-perfo…
Generation and manipulation of squeezed states of light in optical networks for quantum communication and computation
Maxim Raginsky, Prem Kumar
We analyze a fiber-optic component which could find multiple uses in novel information-processing systems utilizing squeezed states of light. Our approach is based on the phenomeno…
InterQnet: A Heterogeneous Full-Stack Approach to Co-designing Scalable Quantum Networks
Joaquin Chung, Daniel Dilley, Ely Eastman +21
Quantum communications have progressed significantly, moving from a theoretical concept to small-scale experiments to recent metropolitan-scale demonstrations. As the technology ma…
FDTD Simulation of Thermal Noise in Open Cavities
Jonathan Andreasen, Hui Cao, Allen Taflove +2
A numerical model based on the finite-difference time-domain (FDTD) method is developed to simulate thermal noise in open cavities owing to output coupling. The absorbing boundary…
Multidimensional mode-separable frequency conversion for high-speed quantum communication
Paritosh Manurkar, Nitin Jain, Michael Silver +5
Quantum frequency conversion (QFC) of photonic signals preserves quantum information while simultaneously changing the signal wavelength. A common application of QFC is to translat…
Raman-noise induced quantum limits for chi^3 nondegenerate phase-sensitive amplification and quadrature squeezing
Paul L. Voss, Kahraman G. Köprülü, Prem Kumar
We present a quantum theory of nondegenerate phase-sensitive parametric amplification in a chi^3 nonlinear medium. The non-zero response time of the Kerr chi^3 nonlinearity determi…
Programmable optical waveform reshaping on a picosecond timescale
Paritosh Manurkar, Nitin Jain, Prem Kumar +1
We experimentally demonstrate temporal reshaping of optical waveforms in the telecom wavelength band using the principle of quantum frequency conversion. The reshaped optical pulse…
Local Harmonic Approximation to Quantum Mean Force Gibbs State
Prem Kumar
When the strength of interaction between a quantum system and bath is non-negligible, the equilibrium state can deviate from the Gibbs state. But the expression of such a mean forc…
Entangled Photon Polarimetry
Joseph B. Altepeter, Neal N. Oza, Milja Medic +2
We construct an entangled photon polarimeter capable of monitoring a two-qubit quantum state in real time. Using this polarimeter, we record a nine frames-per-second video of a two…
Interaction-Free All-Optical Switching via Quantum-Zeno Effect
Yu-Ping Huang, Joseph B. Altepeter, Prem Kumar
We propose a novel interaction-free scheme for all-optical switching which does not rely on the physical coupling between signal and control waves. The interaction-free nature of t…
Quantum teleportation coexisting with classical communications in optical fiber
Jordan M. Thomas, Fei I. Yeh, Jim Hao Chen +4
The ability for quantum and conventional networks to operate in the same optical fibers would aid the deployment of quantum network technology on a large scale. Quantum teleportati…
Development of Quantum InterConnects for Next-Generation Information Technologies
David Awschalom, Karl K. Berggren, Hannes Bernien +32
Just as classical information technology rests on a foundation built of interconnected information-processing systems, quantum information technology (QIT) must do the same. A crit…