Mirko Consiglio - Academia.edu (original) (raw)

Papers by Mirko Consiglio

arXiv (Cornell University), May 28, 2023

Preparing the Gibbs state of an interacting quantum manybody system on noisy intermediate-scale q... more Preparing the Gibbs state of an interacting quantum manybody system on noisy intermediate-scale quantum (NISQ) devices is a crucial task for exploring the thermodynamic properties in the quantum regime. It encompasses understanding protocols such as thermalization and out-of-equilibrium thermodynamics, as well as sampling from faithfully prepared Gibbs states could pave the way to providing useful resources for quantum algorithms. Variational quantum algorithms (VQAs) show the most promise in efficiently preparing Gibbs states, however, there are many different approaches that could be applied to effectively determine and prepare Gibbs states on a NISQ computer. In this paper, we provide a concise overview of the algorithms capable of preparing Gibbs states, including joint Hamiltonian evolution of a system-environment coupling, quantum imaginary time evolution, and modern VQAs utilizing the Helmholtz free energy as a cost function, among others. Furthermore, we perform a benchmark of one of the latest variational Gibbs state preparation algorithms, developed by Consiglio et al. [16], by applying it to the spin 1/2 one-dimensional XY model.

arXiv (Cornell University), Mar 20, 2023

arXiv (Cornell University), Dec 4, 2021

Quantum information processing protocols are efficiently implemented on spin-1 2 networks. A quan... more Quantum information processing protocols are efficiently implemented on spin-1 2 networks. A quantum communication protocol generally involves a certain number of parties having local access to a subset of a larger system, whose intrinsic dynamics are exploited in order to perform a specific task. In this chapter, we address such a scenario with the quantum dynamical map formalism, where the dynamics of the larger system is expressed as a quantum map acting on the parties' access to their respective subsets of spins. We reformulate widely investigated protocols, such as one-qubit quantum state transfer and two-qubit entanglement distribution, with the quantum map formalism and demonstrate its usefulness in exploring less investigated protocols such as multi-qubit entanglement generation. Due to their formal analogy to quantum registers, quantum spin-1 2 networks have become the ideal testbed for many quantum information processing (QIP) protocols, ranging from quantum key distribution to quantum computation [1]. The availability of accurate theoretical models governing their dynamics, being amenable to

Entropy

The distribution of entangled states is a key task of utmost importance for many quantum informat... more The distribution of entangled states is a key task of utmost importance for many quantum information processing protocols. A commonly adopted setup for distributing quantum states envisages the creation of the state in one location, which is then sent to (possibly different) distant receivers through some quantum channels. While it is undoubted and, perhaps, intuitively expected that the distribution of entangled quantum states is less efficient than that of product states, a thorough quantification of this inefficiency (namely, of the difference between the quantum-state transfer fidelity for entangled and factorized states) has not been performed. To this end, in this work, we consider n-independent amplitude-damping channels, acting in parallel, i.e., each, locally, on one part of an n-qubit state. We derive exact analytical results for the fidelity decrease, with respect to the case of product states, in the presence of entanglement in the initial state, for up to four qubits. I...

Cornell University - arXiv, Sep 3, 2022

We present the variational separability verifier (VSV), which is a novel variational quantum algo... more We present the variational separability verifier (VSV), which is a novel variational quantum algorithm (VQA) that determines the closest separable state (CSS) of an arbitrary quantum state with respect to the Hilbert-Schmidt distance (HSD). We first assess the performance of the VSV by investigating the convergence of the optimization procedure for Greenberger-Horne-Zeilinger (GHZ) states of up to seven qubits, using both statevector and shot-based simulations. We also numerically determine the CSS of maximally-entangled mixed X-states (X-MEMS), and subsequently use the results of the algorithm to surmise the analytical form of the aforementioned CSS. Our results indicate that current noisy intermediate-scale quantum (NISQ) devices may be useful in addressing the N P-hard full separability problem using the VSV, due to the shallow quantum circuit imposed by employing the destructive SWAP test to evaluate the HSD. The VSV may also possibly lead to the characterization of multipartite quantum states, once the algorithm is adapted and improved to obtain the closest k-separable state (k-CSS) of a multipartite entangled state.

Physical Review A

We present the variational separability verifier (VSV), which is a variational quantum algorithm ... more We present the variational separability verifier (VSV), which is a variational quantum algorithm that determines the closest separable state (CSS) of an arbitrary quantum state with respect to the Hilbert-Schmidt distance (HSD). We first assess the performance of the VSV by investigating the convergence of the optimization procedure for Greenberger-Horne-Zeilinger states of up to seven qubits, using both state-vector and shot-based simulations. We also numerically determine the CSS of maximally entangled mixed X states, and subsequently use the results of the algorithm to surmise the analytical form of the aforementioned CSS. Our results indicate that current noisy intermediate-scale quantum devices may be useful in addressing the NP-hard full separability problem using the VSV, due to the shallow quantum circuit imposed by employing the destructive SWAP test to evaluate the HSD. The VSV may also possibly lead to the characterization of multipartite quantum states, once the algorithm is adapted and improved to obtain the closest k-separable state of a multipartite entangled state.

New Journal of Physics

The transfer of quantum information between different locations is key to many quantum informatio... more The transfer of quantum information between different locations is key to many quantum information processing tasks. Whereas, the transfer of a single qubit state has been extensively investigated, the transfer of a many-body system configuration has insofar remained elusive. We address the problem of transferring the state of n interacting qubits. Both the exponentially increasing Hilbert space dimension, and the presence of interactions significantly scale-up the complexity of achieving high-fidelity transfer. By employing tools from random matrix theory and using the formalism of quantum dynamical maps, we derive a general expression for the average and the variance of the fidelity of an arbitrary quantum state transfer protocol for n interacting qubits. Finally, by adopting a weak-coupling scheme in a spin chain, we obtain the explicit conditions for high-fidelity transfer of three and four interacting qubits.

International Journal of Quantum Information, 2021

Teleporting an unknown qubit state is a paradigmatic quantum information processing task revealin... more Teleporting an unknown qubit state is a paradigmatic quantum information processing task revealing the advantage of quantum communication protocols over their classical counterpart. For a teleportation protocol using a Bell state as quantum channel, the resource has been identified to be the concurrence. However, for mixed multipartite states the lack of computable entanglement measures has made the identification of the quantum resource responsible for this advantage more challenging. Here, by building on previous results showing that localizable concurrence is the necessary resource for controlled quantum teleportation, we show that any teleportation protocol using an arbitrary multipartite state, that includes a Bell measurement, requires a nonvanishing localizable concurrence between two of its parties to perform better than the classical protocol. By first analyzing Greenberger–Horne–Zeilinger (GHZ) channel and GHZ measurement teleportation protocol, in the presence of GHZ-symm...

Mirko Consiglio, ∗ Wayne J. Chetcuti, 3, 4 Carlos Bravo-Prieto, 5 Sergi Ramos-Calderer, 5 Anna Mi... more Mirko Consiglio, ∗ Wayne J. Chetcuti, 3, 4 Carlos Bravo-Prieto, 5 Sergi Ramos-Calderer, 5 Anna Minguzzi, José I. Latorre, 5, 7 Luigi Amico, 7, 8, 9 and Tony J. G. Apollaro † Department of Physics, University of Malta, Msida MSD 2080, Malta Dipartimento di Fisica e Astronomia, Via S. Sofia 64, 95127 Catania, Italy INFN-Sezione di Catania, Via S. Sofia 64, 95127 Catania, Italy Quantum Research Centre, Technology Innovation Institute, Abu Dhabi, UAE Departament de F́ısica Quàntica i Astrof́ısica and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Mart́ı i Franquès 1, 08028 Barcelona, Spain. Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore CNR-MATIS-IMM & INFN-Sezione di Catania, Via S. Sofia 64, 95127 Catania, Italy LANEF ’Chaire d’excellence’, Université Grenoble Alpes, CNRS, 38000 Grenoble, France (Dated: June 30, 2021)