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Francesco De Martini - One of the best experts on this subject based on the ideXlab platform.
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Investigation on the Quantum-to-classical transition by optical parametric amplification: Generation and detection of multiphoton Quantum Superposition
Optics Communications, 2015Co-Authors: Francesco De Martini, Fabio SciarrinoAbstract:Abstract We review an extended research carried out on the theoretical and experimental realization of a macroscopic Quantum Superposition (MQS) made up with photons. The described scheme is based on a nonlinear process, the Quantum injected optical parametric amplification, that transforms the Quantum coherence of a single particle state, i.e. a Micro-qubit, into a Macro-qubit, consisting in a large number M of photons in Quantum Superposition. Since the adopted scheme was found resilient to decoherence, the MQS demonstration was carried out experimentally at room temperature with M ≥ 10 4 . This result elicited an extended study on Quantum cloning, Quantum amplification and Quantum decoherence. The MQS interference patterns for large M were revealed in the experiment and the bipartite Micro–Macro entanglement was also demonstrated for a limited number of generated particles. At last, the perspectives opened by this new method are considered in the view of further studies on Quantum foundations and Quantum measurement.
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Entanglement and Quantum Superposition of a Macroscopic - Macroscopic system
Foundations of Physics, 2010Co-Authors: Francesco De MartiniAbstract:Two Quantum Macro-states and their Macroscopic Quantum Superpositions (MQS) localized in two far apart, space-like separated sites can be non-locally correlated by any entangled couple of single-particles having interacted in the past. This novel “Macro-Macro” paradigm is investigated on the basis of a recent study on an entangled Micro-Macro system involving N≈105 particles. Crucial experimental issues as the violation of Bell’s inequalities by the Macro-Macro system are considered.
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Coherent scattering of a multiphoton Quantum Superposition by a mirror BEC.
Physical review letters, 2010Co-Authors: Francesco De Martini, Fabio Sciarrino, Chiara Vitelli, Francesco Saverio CataliottiAbstract:We present the proposition of an experiment in which the multiphoton Quantum Superposition consisting of N approximately 10{5} particles generated by a Quantum-injected optical parametric amplifier, seeded by a single-photon belonging to an Einstein-Podolsky-Rosen entangled pair, is made to interact with a mirror-Bose-Einstein condensate (BEC) shaped as a Bragg interference structure. The overall process will realize a macroscopic Quantum Superposition involving a microscopic single-photon state of polarization entangled with the coherent macroscopic transfer of momentum to the BEC structure, acting in spacelike separated distant places.
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Decoherence, environment-induced superselection, and classicality of a macroscopic Quantum Superposition generated by Quantum cloning
Physical Review A, 2009Co-Authors: Francesco De Martini, Fabio Sciarrino, Nicolò SpagnoloAbstract:The high resilience to decoherence shown by a recently discovered macroscopic Quantum Superposition (MQS) generated by a Quantum-injected optical parametric amplifier and involving a number of photons in excess of $5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ motivates the present theoretical and numerical investigation. The results are analyzed in comparison with the properties of the MQS based on $|\ensuremath{\alpha}⟩$ and N-photon maximally entangled states (NOON), in the perspective of the comprehensive theory of the subject by Zurek. In that perspective the concepts of ``pointer state'' and ``environment-induced superselection'' are applied to the new scheme.
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Decoherence of a Macroscopic Quantum Superposition
arXiv: Quantum Physics, 2008Co-Authors: Francesco De Martini, Fabio Sciarrino, Nicolò SpagnoloAbstract:The high resilience to de-coherence shown by a recently discovered Macroscopic Quantum Superposition (MQS) involving a number of photons in excess of 5 x 10^4 motivates the present theoretical and numerical investigation. The results are placed in close comparison with the properties of the well known MQS based on |alpha> states. The very critical decoherence properties of the latter MQS are found to be fully accounted for, in a direct a simple way, by a unique "universal" function: indeed a new property of the Quantum "coherent states".
Zhang-qi Yin - One of the best experts on this subject based on the ideXlab platform.
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Quantum Superposition, entanglement, and state teleportation of a microorganism on an electromechanical oscillator
Science Bulletin, 2016Co-Authors: Zhang-qi YinAbstract:Schrodinger’s thought experiment to prepare a cat in a Superposition of both alive and dead states reveals profound consequences of Quantum mechanics and has attracted enormous interests. Here we propose a straightforward method to create Quantum Superposition states of a living microorganism by putting a small cryopreserved bacterium on top of an electromechanical oscillator. Our proposal is based on recent developments that the center-of-mass oscillation of a 15-μm-diameter aluminum membrane has been cooled to its Quantum ground state (Teufel et al. in Nature 475:359, 2011), and entangled with a microwave field (Palomaki et al. in Science 342:710, 2013). A microorganism with a mass much smaller than the mass of the electromechanical membrane will not significantly affect the quality factor of the membrane and can be cooled to the Quantum ground state together with the membrane. Quantum Superposition and teleportation of its center-of-mass motion state can be realized with the help of superconducting microwave circuits. More importantly, the internal states of a microorganism, such as the electron spin of a glycine radical, can be entangled with its center-of-mass motion and teleported to a remote microorganism. Our proposal can be realized with state-of-the-art technologies. The proposed setup is a Quantum-limited magnetic resonance force microscope. Since internal states of an organism contain information, our proposal also provides a scheme for teleporting information or memories between two remote organisms.
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Quantum Superposition entanglement and state teleportation of a microorganism on an electromechanical oscillator
arXiv: Quantum Physics, 2015Co-Authors: Zhang-qi YinAbstract:Schr\"odinger's thought experiment to prepare a cat in a Superposition of both alive and dead states reveals profound consequences of Quantum mechanics and has attracted enormous interests. Here we propose a straightforward method to create Quantum Superposition states of a living microorganism by putting a small cryopreserved bacterium on top of an electromechanical oscillator. Our proposal is based on recent developments that the center-of-mass oscillation of a 15-$\mu$m-diameter aluminium membrane has been cooled to its Quantum ground state [Nature 475: 359 (2011)], and entangled with a microwave field [Science 342: 710 (2013)]. A microorganism with a mass much smaller than the mass of the electromechanical membrane will not significantly affect the quality factor of the membrane and can be cooled to the Quantum ground state together with the membrane. Quantum Superposition and teleportation of its center-of-mass motion state can be realized with the help of superconducting microwave circuits. More importantly, the internal states of a microorganism, such as the electron spin of a glycine radical, can be entangled with its center-of-mass motion and teleported to a remote microorganism. Our proposal can be realized with state-of-art technologies. The proposed setup is a Quantum-limited magnetic resonance force microscope. Since internal states of an organism contain information, our proposal also provides a scheme for teleporting information or memories between two remote organisms.
Mateus Araújo - One of the best experts on this subject based on the ideXlab platform.
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Computational advantage from Quantum Superposition of multiple temporal orders of photonic gates.
arXiv: Quantum Physics, 2021Co-Authors: M. M. Taddei, Mateus Araújo, Jaime Cariñe, D. Martínez, Tania García, Nayda Guerrero, Alastair A. Abbott, Cyril Branciard, E. S. Gómez, Stephen P. WalbornAbstract:Models for Quantum computation with circuit connections subject to the Quantum Superposition principle have been recently proposed. There, a control Quantum system can coherently determine the order in which a target Quantum system undergoes $N$ gate operations. This process, known as the Quantum $N$-switch, is a resource for several information-processing tasks. In particular, it provides a computational advantage -- over fixed-gate-order Quantum circuits -- for phase-estimation problems involving $N$ unknown unitary gates. However, the corresponding algorithm requires an experimentally unfeasible target-system dimension (super)exponential in $N$. Here, we introduce a promise problem for which the Quantum $N$-switch gives an equivalent computational speed-up with target-system dimension as small as 2 regardless of $N$. We use state-of-the-art multi-core optical-fiber technology to experimentally demonstrate the Quantum $N$-switch with $N=4$ gates acting on a photonic-polarization qubit. This is the first observation of a Quantum Superposition of more than $N=2$ temporal orders, demonstrating its usefulness for efficient phase-estimation.
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Computational Advantage from the Quantum Superposition of Multiple Temporal Orders of Photonic Gates
PRX Quantum, 2021Co-Authors: M. M. Taddei, Mateus Araújo, Jaime Cariñe, D. Martínez, Tania García, Nayda Guerrero, Cyril Branciard, Alastair Abbott, Esteban Gómez, Stephen P. WalbornAbstract:Models for Quantum computation with circuit connections subject to the Quantum Superposition principle have recently been proposed. In them, a control Quantum system can coherently determine the order in which a target Quantum system undergoes $N$ gate operations. This process, known as the Quantum $N$-switch, is a resource for several information-processing tasks. In particular, it provides a computational advantage---over fixed-gate-order Quantum circuits—for phase-estimation problems involving $N$ unknown unitary gates. However, the corresponding algorithm requires an experimentally unfeasible target-system dimension (super)exponential in $N$. Here, we introduce a promise problem for which the Quantum $N$-switch gives an equivalent computational speedup with target-system dimension as small as 2 regardless of $N$. We use state-of-the-art multicore optical-fiber technology to experimentally demonstrate the Quantum $N$-switch with $N=4$ gates acting on a photonic-polarization qubit. This is the first observation of a Quantum Superposition of more than $N=2$ temporal orders, demonstrating its usefulness for efficient phase estimation.
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experimental computational advantage from Superposition of multiple temporal orders of Quantum gates
arXiv: Quantum Physics, 2020Co-Authors: M. M. Taddei, Mateus Araújo, Jaime Cariñe, D. Martínez, Tania García, Nayda Guerrero, Alastair A. Abbott, Cyril Branciard, E. S. Gómez, Stephen P. WalbornAbstract:Advanced models for Quantum computation where even the circuit connections are subject to the Quantum Superposition principle have been recently introduced. There, a control Quantum system can coherently control the order in which a target Quantum system undergoes $N$ gate operations. This process is known as the Quantum $N$-switch, and has been identified as a resource for several information-processing tasks. In particular, the Quantum $N$-switch provides a computational advantage -- over all circuits with fixed gate orders -- for phase-estimation problems involving $N$ unknown unitary gates. However, the corresponding algorithm requires the target-system dimension to grow (super-)exponentially with $N$, making it experimentally demanding. In fact, all implementations of the Quantum $N$-switch reported so far have been restricted to $N=2$. Here, we introduce a promise problem for which the Quantum $N$-switch gives an equivalent computational speed-up but where the target-system dimension can be as small as 2 regardless of $N$. We use state-of-the-art multi-core optical fiber technology to experimentally demonstrate the Quantum $N$-switch with $N = 4$ gates acting on a photonic-polarization qubit. This is the first observation of a Quantum Superposition of more than 2 temporal orders, and also demonstrates its usefulness for efficient phase-estimation.
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Exponential Communication Complexity Advantage from Quantum Superposition of the Direction of Communication.
Physical review letters, 2016Co-Authors: Philippe Allard Guérin, Adrien Feix, Mateus Araújo, Časlav BruknerAbstract:In communication complexity, a number of distant parties have the task of calculating a distributed function of their inputs, while minimizing the amount of communication between them. It is known that with Quantum resources, such as entanglement and Quantum channels, one can obtain significant reductions in the communication complexity of some tasks. In this work, we study the role of the Quantum Superposition of the direction of communication as a resource for communication complexity. We present a tripartite communication task for which such a Superposition allows for an exponential saving in communication, compared to one-way Quantum (or classical) communication; the advantage also holds when we allow for protocols with bounded error probability.
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Quantum Superposition of the order of parties as a communication resource
Physical Review A, 2015Co-Authors: Adrien Feix, Mateus Araújo, Časlav BruknerAbstract:In a variant of communication complexity tasks, two or more separated parties cooperate to compute a function of their local data, using a limited amount of communication. It is known that communication of Quantum systems and shared entanglement can increase the probability for the parties to arrive at the correct value of the function, compared to classical resources. Here we show that Quantum Superpositions of the direction of communication between parties can also serve as a resource to improve the probability of success. We present a tripartite task for which such a Superposition provides an advantage compared to the case where the parties communicate in a fixed order. In a more general context, our result also provides the first semi-device-independent certification of the absence of a definite order of communication.
S Padua - One of the best experts on this subject based on the ideXlab platform.
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multiparticle Quantum Superposition and stimulated entanglement by parity selective amplification of entangled states
Physical Review Letters, 2001Co-Authors: Francesco De Martini, Giovanni Di Giuseppe, S PaduaAbstract:Since the golden years of Quantum mechanics the interference of classically distinguishable Quantum states, first introduced by the famous “Schrodinger Cat” apologue [1], has been the object of extensive theoretical studies and recognized as a major conceptual paradigm of physics [2]. In modern times the sciences of Quantum information and Quantum computation deal precisely with collective processes involving a multiplicity of interfering states, generally mutually entangled and rapidly dephased by decoherence. In many respects the experimental implementation of this intriguing classical-Quantum condition represents today an unsolved problem in spite of recent successful studies carried out mostly with atoms [3]. A nearly decoherence-free all-optical scheme based on the process of the Quantum injected optical parametric amplification (OPA) of a single photon in a Quantum Superposition state, i.e., a qubit, has been proposed [4]. As a relevant step forward in the realization of the Quantum injection scheme, the present work reports a novel OPA system that transforms any input linear-polarization p entangled, 2-photon state (e-bit) into a Quantum Superposition of p-entangled, multiphonon states, indeed a Schrodinger Cat state (S-Cat) here referred to as a “large” (or “massive”) qubit: M-qubit. In order to implement the new scheme we adopted the single nonlinear (NL) crystal configuration shown in Fig. 1. According to this scheme the exciting UV optical beam, the pump of the OPA interaction, was first injected at a low intensity level into the NL crystal with the wave vector (wv) k 0 oriented towards the left (L) side of the figure. By this process, commonly referred to as spontaneous parametric down conversion (SPDC) or L amplification, single photon pairs in p-entangled states were generated. The UV beam was then back reflected with the wv kp oriented towards the right (R) direction, and tightly refocused into the NL crystal together with the two back-reflected SPDC generated photons. This provided the main amplification (R amplification) of the Quantum-injected e-bit states and their final transformation into the multiphoton S-Cat states. Of course, since SPDC is an aleatory process it was necessary to postselect the amplified S-Cat states against the squeezed-vacuum (s-v) noise arising from the R amplification of the vacuum state in the absence of the injected particles. This difficult problem was solved by implementing at the output of our system an efficient parityselective device, usually referred to as nonlocal entangled interferometer (NEIF) [5]. In the language of electrical engineering, NEIF conveyed on different output channels the s-v “noise” and the “signal,” viz. the amplified e-bit state. This resulted in the final detection of the S-Cat macrostate with a large, virtually infinite signal-to-noise ratio SN. Let us now venture into a more detailed description of the apparatus. A NL beta-barium-borate (BBO) crystal slab cut for Type II phase matching and 1.5 mm thick, was excited in both left and right directions by an UV beam back reflected by a spherical mirror Mp with curvature radius rp 30 cm. A computer controlled mount allowed micrometric displacements of Mp along the axis Z parallel to the wv kp of the UV beam. This one was generated by a Ti:Sa coherent MIRA mode-locked
Leihai Nie - One of the best experts on this subject based on the ideXlab platform.
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Optimizing Quantum Programs against Decoherence: Delaying Qubits into Quantum Superposition
2019 International Symposium on Theoretical Aspects of Software Engineering (TASE), 2019Co-Authors: Yu Zhang, Haowei Deng, Haoze Song, Leihai NieAbstract:Quantum computing technology has reached a second renaissance in the last decade. However, in the NISQ era pointed out by John Preskill in 2018, Quantum noise and decoherence, which affect the accuracy and execution effect of Quantum programs, cannot be ignored and corrected by the near future NISQ computers. In order to let users more easily write Quantum programs, the compiler and runtime system should consider underlying Quantum hardware features such as decoherence. To address the challenges posed by decoherence, in this paper, we propose and prototype QLifeReducer to minimize the qubit lifetime in the input OpenQASM program by delaying qubits into Quantum Superposition. QLifeReducer includes three core modules, i.e.,the parser, parallelism analyzer and transformer. It introduces the layered bundle format to express the Quantum program, where a set of parallelizable Quantum operations is packaged into a bundle. We evaluate Quantum programs before and after transformed by QLifeReducer on both real IBM Q 5 Tenerife and the self-developed simulator. The experimental results show that QLifeReducer reduces the error rate of a Quantum program when executed on IBMQ 5 Tenerife by 11%; and can reduce the longest qubit lifetime as well as average qubit lifetime by more than 20% on most Quantum workloads.