Publications old

@article{https://doi.org/10.48550/arxiv.2203.03364,

title = {Optimized state transfer in systems of ultrastrongly coupled matter and radiation},

author = {Luigi Giannelli and Jishnu Rajendran and Nicola Macrì and Giuliano Benenti and Simone Montangero and Elisabetta Paladino and Giuseppe Falci},

url = {https://arxiv.org/abs/2203.03364},

doi = {10.48550/ARXIV.2203.03364},

year  = {2022},

date = {2022-01-01},

publisher = {arXiv},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{jamotte_strain_2022,

title = {Strain and pseudo-magnetic fields in optical lattices from density-assisted tunneling},

author = {Maxime Jamotte and Nathan Goldman and Marco Di_Liberto},

url = {https://www.nature.com/articles/s42005-022-00802-9},

doi = {10.1038/s42005-022-00802-9},

issn = {2399-3650},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Communications Physics},

volume = {5},

number = {1},

pages = {30},

abstract = {Abstract 

 Applying time-periodic modulations is routinely used to control and design synthetic matter in quantum-engineered settings. In lattice systems, this approach is explored to engineer band structures with non-trivial topological properties, but also to generate exotic interaction processes. A prime example is density-assisted tunneling, by which the hopping amplitude of a particle between neighboring sites explicitly depends on their respective occupations. Here, we show how density-assisted tunneling can be tailored in view of simulating the effects of strain in synthetic graphene-type systems. Specifically, we consider a mixture of two atomic species on a honeycomb optical lattice: one species forms a Bose-Einstein condensate in an anisotropic harmonic trap, whose inhomogeneous density profile induces an effective uniaxial strain for the second species through density-assisted tunneling processes. In direct analogy with strained graphene, the second species experiences a pseudo-magnetic field, hence exhibiting relativistic Landau levels and the valley Hall effect. Our proposed scheme introduces a unique platform for the investigation of strain-induced gauge fields, opening the door to future studies of their possible interplay with quantum fluctuations and collective excitations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marshall2021,

title = {Macroscopic Hyperpolarization Enhanced with Quantum Optimal Control},

author = {Alastair Marshall and Thomas Reisser and Phila Rembold and Christoph Müller and Jochen Scheuer and Martin Gierse and Tim Eichhorn and Jakob M. Steiner and Patrick Hautle and Tommaso Calarco and Fedor Jelezko and Martin B. Plenio and Simone Montangero and Ilai Schwartz and Matthias M. Müller and Philipp Neumann},

url = {http://arxiv.org/abs/2112.15021},

year  = {2021},

date = {2021-12-30},

pages = {1–15},

abstract = {Hyperpolarization of nuclear spins enhances nuclear magnetic resonance signals, which play a key role for imaging and spectroscopy in the natural and life sciences. This signal amplification unlocks previously inaccessible techniques, such as metabolic imaging of cancer cells. In this work, electron spins from the photoexcited triplet state of pentacene-doped naphthalene crystals are used to polarize surrounding protons. As existing strategies are rendered less effective by experimental constraints, they are replaced with optimal control pulses designed with RedCRAB. In contrast to previous optimal control approaches, which consider an average single nucleus, this closed-loop optimization is macroscopic. A 28% improvement in signal and 15% faster polarization rate is observed. Additionally, a strategy called Autonomously-optimized Repeated Linear Sweep (ARISE) is introduced to efficiently tailor existing hyperpolarization sequences in the presence of experimental uncertainty to enhance their performance. ARISE is expected to be broadly applicable in many experimental settings.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{notarnicola_randomized_2021,

title = {A randomized measurement toolbox for Rydberg quantum technologies},

author = {Simone Notarnicola and Andreas Elben and Thierry Lahaye and Antoine Browaeys and Simone Montangero and Benoit Vermersch},

url = {http://arxiv.org/abs/2112.11046},

year  = {2021},

date = {2021-12-21},

pages = {1–9},

abstract = {We present a toolbox to probe quantum many-body states implemented on Rydberg-atoms quantum hardware via randomized measurements. We illustrate the efficacy of this measurement toolbox in the context of probing entanglement, via the estimation of the purity, and of verifying a ground-state preparation using measurements of the Hamiltonian variance. To achieve this goal, we develop and discuss in detail a protocol to realize independent, local unitary rotations. We benchmark the protocol by investigating the ground state of the one-dimensional SSH model, recently realized on a chain of Rydberg atom. We probe the robustness of our toolbox by taking into account experimental imperfections, such as pulse fluctuations and measurement errors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zuliani2021a,

title = {Quantum-inspired machine learning on high-energy physics data},

author = {Timo Felser and Marco Trenti and Lorenzo Sestini and Alessio Gianelle and Davide Zuliani and Donatella Lucchesi and Simone Montangero},

url = {http://dx.doi.org/10.1038/s41534-021-00443-w},

doi = {10.1038/s41534-021-00443-w},

issn = {2056-6387},

year  = {2021},

date = {2021-12-15},

volume = {7},

number = {1},

pages = {111},

abstract = {Tensor Networks, a numerical tool originally designed for simulating quantum many-body systems, have recently been applied to solve Machine Learning problems. Exploiting a tree tensor network, we apply a quantum-inspired machine learning technique to a very important and challenging big data problem in high-energy physics: the analysis and classification of data produced by the Large Hadron Collider at CERN. In particular, we present how to effectively classify so-called b-jets, jets originating from b-quarks from proton–proton collisions in the LHCb experiment, and how to interpret the classification results. We exploit the Tensor Network approach to select important features and adapt the network geometry based on information acquired in the learning process. Finally, we show how to adapt the tree tensor network to achieve optimal precision or fast response in time without the need of repeating the learning process. These results pave the way to the implementation of high-frequency real-time applications, a key ingredient needed among others for current and future LHCb event classification able to trigger events at the tens of MHz scale.},

note = {Publisher: Sissa Medialab 

Place: Trieste, Italy},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Magnifico2020,

title = {Lattice quantum electrodynamics in (3+1)-dimensions at finite density with tensor networks},

author = {Giuseppe Magnifico and Timo Felser and Pietro Silvi and Simone Montangero},

url = {http://arxiv.org/abs/2011.10658},

doi = {10.1038/s41467-021-23646-3},

issn = {2041-1723},

year  = {2021},

date = {2021-12-14},

volume = {12},

number = {1},

pages = {3600},

abstract = {Gauge theories are of paramount importance in our understanding of fundamental constituents of matter and their interactions. However, the complete characterization of their phase diagrams and the full understanding of non-perturbative effects are still debated, especially at finite charge density, mostly due to the sign-problem affecting Monte Carlo numerical simulations. Here, we report the Tensor Network simulation of a three dimensional lattice gauge theory in the Hamiltonian formulation including dynamical matter: Using this sign-problem-free method, we simulate the ground states of a compact Quantum Electrodynamics at zero and finite charge densities, and address fundamental questions such as the characterization of collective phases of the model, the presence of a confining phase at large gauge coupling, and the study of charge-screening effects.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rigobello2021,

title = {Entanglement generation in QED scattering processes},

author = {Marco Rigobello and Simone Notarnicola and Giuseppe Magnifico and Simone Montangero},

url = {http://arxiv.org/abs/2105.03445},

doi = {10.1103/PhysRevD.104.114501},

issn = {2470-0010},

year  = {2021},

date = {2021-12-06},

volume = {104},

number = {11},

pages = {114501},

abstract = {We study real-time meson-meson scattering processes in $(1+1)$-dimensional QED by means of Tensor Networks. We prepare initial meson wave packets with given momentum and position introducing an approximation based on the free fermions model. Then, we compute the dynamics of two initially separated colliding mesons, observing a rich phenomenology as the interaction strength and the initial states are varied in the weak and intermediate coupling regimes. Finally, we consider elastic collisions and measure some scattering amplitudes as well as the entanglement generated by the process. Remarkably, we identify two different regimes for the asymptotic entanglement between the outgoing mesons: it is perturbatively small below a threshold coupling, past which its growth as a function of the coupling abruptly accelerates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hillberry2020,

title = {Entangled quantum cellular automata, physical complexity, and Goldilocks rules},

author = {Logan E. Hillberry and Matthew T. Jones and David L. Vargas and Patrick Rall and Nicole Yunger Halpern and Ning Bao and Simone Notarnicola and Simone Montangero and Lincoln D. Carr},

url = {http://arxiv.org/abs/2005.01763},

doi = {10.1088/2058-9565/ac1c41},

issn = {2058-9565},

year  = {2021},

date = {2021-10-01},

volume = {6},

number = {4},

pages = {045017},

abstract = {Cellular automata are interacting classical bits that display diverse behaviors, from fractals to random-number generators to Turing-complete computation. We introduce entangled quantum cellular automata subject to Goldilocks rules, tradeoffs of the kind underpinning biological, social, and economic complexity. Tweaking digital and analog quantum-computing protocols generates persistent entropy fluctuations; robust dynamical features, including an entangled breather; and network structure and dynamics consistent with complexity. Present-day quantum platforms—Rydberg arrays, trapped ions, and superconducting qubits—can implement Goldilocks protocols, which generate quantum many-body states with rich entanglement and structure. Moreover, the complexity studies reported here underscore an emerging idea in many-body quantum physics: some systems fall outside the integrable/chaotic dichotomy.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Cataldi2021,

title = {Hilbert curve vs Hilbert space: exploiting fractal 2D covering to increase tensor network efficiency},

author = {Giovanni Cataldi and Ashkan Abedi and Giuseppe Magnifico and Simone Notarnicola and Nicola Dalla Pozza and Vittorio Giovannetti and Simone Montangero},

url = {http://arxiv.org/abs/2105.02239},

doi = {10.22331/q-2021-09-29-556},

issn = {2521-327X},

year  = {2021},

date = {2021-09-29},

volume = {5},

pages = {556},

abstract = {We present a novel mapping for studying 2D many-body quantum systems by solving an effective, one-dimensional long-range model in place of the original two-dimensional short-range one. In particular, we address the problem of choosing an efficient mapping from the 2D lattice to a 1D chain that optimally preserves the locality of interactions within the TN structure. By using Matrix Product States (MPS) and Tree Tensor Network (TTN) algorithms, we compute the ground state of the 2D quantum Ising model in transverse field with lattice size up to 64 × 64 , comparing the results obtained from different mappings based on two space-filling curves, the snake curve and the Hilbert curve. We show that the locality-preserving properties of the Hilbert curve leads to a clear improvement of numerical precision, especially for large sizes, and turns out to provide the best performances for the simulation of 2D lattice systems via 1D TN structures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{montangero_loop-free_2021,

title = {Loop-free tensor networks for high-energy physics},

author = {Simone Montangero and Enrique Rico and Pietro Silvi and Astronomia G Galilei and Simone Montangero},

year  = {2021},

date = {2021-09-24},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pizzamiglio2021,

title = {Dynamical localization simulated on actual quantum hardware},

author = {Andrea Pizzamiglio and Su Yeon Chang and Maria Bondani and Simone Montangero and Dario Gerace and Giuliano Benenti},

doi = {10.3390/e23060654},

issn = {10994300},

year  = {2021},

date = {2021-05-23},

volume = {23},

number = {6},

pages = {1–9},

abstract = {Quantum computers are invaluable tools to explore the properties of complex quantum systems. We show that dynamical localization of the quantum sawtooth map, a highly sensitive quantum coherent phenomenon, can be simulated on actual, small-scale quantum processors. Our results demonstrate that quantum computing of dynamical localization may become a convenient tool for evaluating advances in quantum hardware performances.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Borselli2021,

title = {Two-Particle Interference with Double Twin-Atom Beams},

author = {F Borselli and M Maiwöger and T Zhang and P Haslinger and V Mukherjee and A Negretti and S Montangero and T Calarco and I Mazets and M Bonneau and J Schmiedmayer},

url = {https://doi.org/10.1103/PhysRevLett.126.083603},

doi = {10.1103/PhysRevLett.126.083603},

issn = {10797114},

year  = {2021},

date = {2021-02-23},

volume = {126},

number = {8},

pages = {083603},

abstract = {We demonstrate a source for correlated pairs of atoms characterized by two opposite momenta and two spatial modes forming a Bell state only involving external degrees of freedom. We characterize the state of the emitted atom beams by observing strong number squeezing up to -10 dB in the correlated two-particle modes of emission. We furthermore demonstrate genuine two-particle interference in the normalized second-order correlation function g(2) relative to the emitted atoms.},

note = {Publisher: American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Collura2019,

title = {On the descriptive power of Neural-Networks as constrained Tensor Networks with exponentially large bond dimension},

author = {Mario Collura and Luca DellÁnna and Timo Felser and Simone Montangero},

url = {http://arxiv.org/abs/1905.11351},

doi = {10.21468/SciPostPhysCore.4.1.001},

issn = {2666-9366},

year  = {2021},

date = {2021-02-02},

volume = {4},

number = {1},

pages = {001},

abstract = {In many cases, neural networks can be mapped into tensor networks with an exponentially large bond dimension. Here, we compare different sub-classes of neural network states, with their mapped tensor network counterpart for studying the ground state of short-range Hamiltonians. We show that when mapping a neural network, the resulting tensor network is highly constrained and thus the neural network states do in general not deliver the naive expected drastic improvement against the state-of-the-art tensor network methods. We explicitly show this result in two paradigmatic examples, the 1D ferromagnetic Ising model and the 2D antiferromagnetic Heisenberg model, addressing the lack of a detailed comparison of the expressiveness of these increasingly popular, variational ansätze.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{di_liberto_non-abelian_2020,

title = {Non-Abelian Bloch oscillations in higher-order topological insulators},

author = {M. Di_Liberto and N. Goldman and G. Palumbo},

doi = {10.1038/s41467-020-19518-x},

issn = {20411723},

year  = {2020},

date = {2020-12-01},

urldate = {2020-12-01},

journal = {Nature Communications},

volume = {11},

number = {1},

abstract = {Bloch oscillations (BOs) are a fundamental phenomenon by which a wave packet undergoes a periodic motion in a lattice when subjected to a force. Observed in a wide range of synthetic systems, BOs are intrinsically related to geometric and topological properties of the underlying band structure. This has established BOs as a prominent tool for the detection of Berry-phase effects, including those described by non-Abelian gauge fields. In this work, we unveil a unique topological effect that manifests in the BOs of higher-order topological insulators through the interplay of non-Abelian Berry curvature and quantized Wilson loops. It is characterized by an oscillating Hall drift synchronized with a topologically-protected inter-band beating and a multiplied Bloch period. We elucidate that the origin of this synchronization mechanism relies on the periodic quantum dynamics of Wannier centers. Our work paves the way to the experimental detection of non-Abelian topological properties through the measurement of Berry phases and center-of-mass displacements.},

note = {arXiv: 2007.00549 

Publisher: Nature Research},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Felser2019,

title = {Two-Dimensional Quantum-Link Lattice Quantum Electrodynamics at Finite Density},

author = {Timo Felser and Pietro Silvi and Mario Collura and Simone Montangero},

url = {http://arxiv.org/abs/1911.09693},

doi = {10.1103/PhysRevX.10.041040},

issn = {2160-3308},

year  = {2020},

date = {2020-11-25},

volume = {10},

number = {4},

pages = {041040},

abstract = {We present an unconstrained tree tensor network approach to the study of lattice gauge theories in two spatial dimensions showing how to perform numerical simulations of theories in presence of fermionic matter and four-body magnetic terms, at zero and finite density, with periodic and open boundary conditions. We exploit the quantum link representation of the gauge fields and demonstrate that a fermionic rishon representation of the quantum links allows us to efficiently handle the fermionic matter while finite densities are naturally enclosed in the tensor network description. We explicit perform calculations for quantum electrodynamics in the spin-one quantum link representation on lattice sizes of up to 16x16 sites, detecting and characterizing different quantum regimes. In particular, at finite density, we detect signatures of a phase separation as a function of the bare mass values at different filling densities. The presented approach can be extended straightforwardly to three spatial dimensions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Felser2020,

title = {Efficient Tensor Network ansatz for high-dimensional quantum many-body problems},

author = {Timo Felser and Simone Notarnicola and Simone Montangero},

url = {http://arxiv.org/abs/2011.08200},

year  = {2020},

date = {2020-11-16},

pages = {1–11},

abstract = {We introduce a novel tensor network structure augmenting the well-established Tree Tensor Network representation of a quantum many-body wave function. The new structure satisfies the area law in high dimensions remaining efficiently manipulatable and scalable. We benchmark this novel approach against paradigmatic two-dimensional spin models demonstrating unprecedented precision and system sizes. Finally, we compute the ground state phase diagram of two-dimensional lattice Rydberg atoms in optical tweezers observing non-trivial phases and quantum phase transitions, providing realistic benchmarks for current and future two-dimensional quantum simulations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Cavinato2021,

title = {Optimizing Radiotherapy Plans for Cancer Treatment with Tensor Networks},

author = {Samuele Cavinato and Timo Felser and Marco Fusella and Marta Paiusco and Simone Montangero},

url = {https://iopscience.iop.org/article/10.1088/1361-6560/ac01f2},

doi = {10.1088/1361-6560/ac01f2},

issn = {0031-9155},

year  = {2020},

date = {2020-10-19},

volume = {66},

number = {12},

pages = {125015},

abstract = {We present a novel application of Tensor Network methods in cancer treatment as a potential tool to solve the dose optimization problem in radiotherapy. In particular, the Intensity-Modulated Radiation Therapy (IMRT) technique - that allows treating irregular and inhomogeneous tumors while reducing the radiation toxicity on healthy organs - is based on the optimization of the radiation beamlets intensities. The optimization aims to maximize the delivery of the therapy dose to cancer while avoiding the organs at risk to prevent their damage by the radiation. Here, we map the dose optimization problem into the search of the ground state of an Ising-like Hamiltonian, describing a system of long-range interacting qubits. Finally, we apply a Tree Tensor Network algorithm to find the ground-state of the Hamiltonian. In particular, we present an anatomical scenario exemplifying a prostate cancer treatment. A similar approach can be applied to future hybrid classical-quantum algorithms, paving the way for the use of quantum technologies in future medical treatments.},

note = {Publisher: IOP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{wintersperger_realization_2020,

title = {Realization of an anomalous Floquet topological system with ultracold atoms},

author = {Karen Wintersperger and Christoph Braun and F. Nur Ünal and André Eckardt and Marco Di_Liberto and Nathan Goldman and Immanuel Bloch and Monika Aidelsburger},

doi = {10.1038/s41567-020-0949-y},

issn = {17452481},

year  = {2020},

date = {2020-10-01},

urldate = {2020-10-01},

journal = {Nature Physics},

volume = {16},

number = {10},

pages = {1058–1063},

abstract = {Coherent control via periodic modulation, also known as Floquet engineering, has emerged as a powerful experimental method for the realization of novel quantum systems with exotic properties. In particular, it has been employed to study topological phenomena in a variety of different platforms. In driven systems, the topological properties of the quasienergy bands can often be determined by standard topological invariants, such as Chern numbers, which are commonly used in static systems. However, due to the periodic nature of the quasienergy spectrum, this topological description is incomplete and new invariants are required to fully capture the topological properties of these driven settings. Most prominently, there are two-dimensional anomalous Floquet systems that exhibit robust chiral edge modes, despite all Chern numbers being equal to zero. Here we realize such a system with bosonic atoms in a periodically driven honeycomb lattice and infer the complete set of topological invariants from energy gap measurements and local Hall deflections.},

note = {arXiv: 2002.09840 

Publisher: Nature Research},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Poschinger,

title = {Demonstration of quantum brachistochrones between distant states of an atom},

author = {Manolo R. Lam and Natalie Peter and Thorsten Groh and Wolfgang Alt and Carsten Robens and Dieter Meschede and Antonio Negretti and Simone Montangero and Tommaso Calarco and Andrea Alberti},

url = {http://arxiv.org/abs/1504.02858},

doi = {10.1103/PhysRevA.92.053423},

issn = {1050-2947},

year  = {2020},

date = {2020-09-04},

volume = {92},

number = {5},

pages = {053423},

abstract = {Transforming an initial quantum state into a target state through the fastest possible route—a quantum brachistochrone—is a fundamental challenge for many technologies based on quantum mechanics. Here, we demonstrate fast coherent transport of an atomic wave packet over a distance of 15 times its size—a paradigmatic case of quantum processes where the target state cannot be reached through a local transformation. Our measurements of the transport fidelity reveal the existence of a minimum duration—a quantum speed limit—for the coherent splitting and recombination of matter waves. We obtain physical insight into this limit by relying on a geometric interpretation of quantum state dynamics. These results shed light upon a fundamental limit of quantum state dynamics and are expected to find relevant applications in quantum sensing and quantum computing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Banuls2019,

title = {Simulating lattice gauge theories within quantum technologies},

author = {Mari Carmen Bañuls and Rainer Blatt and Jacopo Catani and Alessio Celi and Juan Ignacio Cirac and Marcello Dalmonte and Leonardo Fallani and Karl Jansen and Maciej Lewenstein and Simone Montangero and Christine A. Muschik and Benni Reznik and Enrique Rico and Luca Tagliacozzo and Karel Van Acoleyen and Frank Verstraete and Uwe-Jens Wiese and Matthew Wingate and Jakub Zakrzewski and Peter Zoller},

url = {http://arxiv.org/abs/1911.00003},

doi = {10.1140/epjd/e2020-100571-8},

issn = {1434-6060},

year  = {2020},

date = {2020-08-04},

volume = {74},

number = {8},

pages = {165},

abstract = {Lattice gauge theories, which originated from particle physics in the context of Quantum Chromodynamics (QCD), provide an important intellectual stimulus to further develop quantum information technologies. While one long-term goal is the reliable quantum simulation of currently intractable aspects of QCD itself, lattice gauge theories also play an important role in condensed matter physics and in quantum information science. In this way, lattice gauge theories provide both motivation and a framework for interdisciplinary research towards the development of special purpose digital and analog quantum simulators, and ultimately of scalable universal quantum computers. In this manuscript, recent results and new tools from a quantum science approach to study lattice gauge theories are reviewed. Two new complementary approaches are discussed: first, tensor network methods are presented - a classical simulation approach - applied to the study of lattice gauge theories together with some results on Abelian and non-Abelian lattice gauge theories. Then, recent proposals for the implementation of lattice gauge theory quantum simulators in different quantum hardware are reported, e.g., trapped ions, Rydberg atoms, and superconducting circuits. Finally, the first proof-of-principle trapped ions experimental quantum simulations of the Schwinger model are reviewed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}