February 2023 - semfis - Mailing lists@ IFISC

Reminder: PhD Thesis Defense, TODAY - Friday, Feb 24, 2023 at 11:00
by semfis＠ifisc.uib-csic.es 24 Feb '23

24 Feb '23

PhD Thesis Defense on Friday Feb 24, 2023 at 11:00 Place: IFISC Seminar Room Title: Characterization and simulation of multipartite open quantum systems Speaker: Marco Cattaneo, Algorithmiq (Helsinki, Finland), PhD student of UIB (IFISC) and the University of Helsinki Abstract: Motivated by renewed studies on dissipative collective effect and by new discoveries about the features of noise in quantum computers, the interest in multipartite open quantum systems has recently risen. A dissipative collective effect may be defined as the coherent interference of the emissions (and/or absorptions) of many quantum particles interacting with external environments. Multipartite open quantum systems are open systems made of multiple subsystems, which can interact with each other and at the same time may be coupled to local and/or collective environments. The characterization and simulation of the dynamics of multipartite open quantum systems is the topic of this doctoral dissertation. The thesis addresses methodological questions, phenomenological predictions, and also presents an experimental implementation on a quantum computer. These contributions include the description and characterization of a general master equation for Markovian multipartite open quantum systems, and some new procedures for the analog and digital quantum simulation thereof.&nbsp; Jury:&nbsp;Anna Sanpera (UAB, Spain),&nbsp;Paolo Muratore (University of Helsinki, Finland), John Goold (Trinity College Dublin, Ireland) Supervisors:&nbsp; S. Maniscalco, R. Zambrini, G.L. Giorgi, M.A.C. Rossi Presential in the&nbsp; IFISC seminar room with parallel Zoom stream at https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09 &nbsp; &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/characterization-and-simulation-of-multipartite-op/

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Reminder: Talk, TODAY - Monday, Feb 20, 2023 at 15:00
by semfis＠ifisc.uib-csic.es 20 Feb '23

20 Feb '23

Talk on Monday Feb 20, 2023 at 15:00 Place: Zoom Seminar Title: Experimental investigation of a microring-based time-delay reservoir computing Speaker: Giovanni Donati, IFISC (CSIC-UIB) - University of Trento Abstract: Reservoir computing is a paradigm that simplifies the training of recurrent neural networks. Beyond reservoir computing algorithms simulated on conventional computers, many physical implementations have been realized, where the reservoir is either composed of many physical distinct nodes, or it is folded in the dynamics of only one single node. Here I will present an experimental realization of an optoelectronic reservoir computing system, folded in the dynamics of an integrated silicon microring resonator coupled to an external optical feedback. The performance of the network is evaluated on delayed digital tasks. Online-only&nbsp;seminar: https://uibuniversitat.zoom.us/j/87008849910 Url event:https://ifisc.uib-csic.es/en/events/seminars/experimental-investigation-of-a-microring-based-ti/

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Reminder: Talk, TODAY - Monday, Feb 20, 2023 at 11:00
by semfis＠ifisc.uib-csic.es 20 Feb '23

20 Feb '23

Talk on Monday Feb 20, 2023 at 11:00 Place: IFISC Seminar Room Title: Entropy estimators for Markovian systems Speaker: Juan I. Gregorio, IFISC (UIB-CSIC) Abstract: <pre> Estimating the entropy of short discrete sequences is an important problem with multiple applications in statistics, linguistics, ecology or neuroscience. Despite the multiple attempts to find an unbiased estimator with minimum mean squared error, the proposed estimators exhibit a performance that greatly vary depending on the type of system under study and the size of the available data. Further, most of the entropy estimators found in the literature assume that the data sequence is generated by independent events. Therefore, their range of applicability to correlated systems has thus far remained unexplored. To fill in this gap, we have analyzed the mostly used entropy estimators for i) binary Markovian sequences and ii) Markovian systems in the undersample regime. We carefully compare the performance of the estimators created for independent systems with a newly proposed entropy formula that takes into account the order of the sequence. We find that this new estimator performs well in terms of the bias but, in the undersample regime, its large dispersion is dominant. Presential in the IFISC seminar room, Zoom stream at: <a class="moz-txt-link-freetext" href="https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09">https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09</a></pre> &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/entropy-estimators-for-markovian-systems/

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Talk on Monday, Feb 20, 2023 at 11:00
by semfis＠ifisc.uib-csic.es 17 Feb '23

17 Feb '23

Talk on Monday Feb 20, 2023 at 11:00 Place: IFISC Seminar Room Title: Entropy estimators for Markovian systems Speaker: Juan I. Gregorio, IFISC (UIB-CSIC) Abstract: <pre> Estimating the entropy of short discrete sequences is an important problem with multiple applications in statistics, linguistics, ecology or neuroscience. Despite the multiple attempts to find an unbiased estimator with minimum mean squared error, the proposed estimators exhibit a performance that greatly vary depending on the type of system under study and the size of the available data. Further, most of the entropy estimators found in the literature assume that the data sequence is generated by independent events. Therefore, their range of applicability to correlated systems has thus far remained unexplored. To fill in this gap, we have analyzed the mostly used entropy estimators for i) binary Markovian sequences and ii) Markovian systems in the undersample regime. We carefully compare the performance of the estimators created for independent systems with a newly proposed entropy formula that takes into account the order of the sequence. We find that this new estimator performs well in terms of the bias but, in the undersample regime, its large dispersion is dominant. Presential in the IFISC seminar room, Zoom stream at: <a class="moz-txt-link-freetext" href="https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09">https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09</a></pre> &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/entropy-estimators-for-markovian-systems/

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Talk on Monday, Feb 20, 2023 at 15:00
by semfis＠ifisc.uib-csic.es 17 Feb '23

17 Feb '23

Talk on Monday Feb 20, 2023 at 15:00 Place: Zoom Seminar Title: Experimental investigation of a microring-based time-delay reservoir computing Speaker: Giovanni Donati, IFISC (CSIC-UIB) - University of Trento Abstract: Reservoir computing is a paradigm that simplifies the training of recurrent neural networks. Beyond reservoir computing algorithms simulated on conventional computers, many physical implementations have been realized, where the reservoir is either composed of many physical distinct nodes, or it is folded in the dynamics of only one single node. Here I will present an experimental realization of an optoelectronic reservoir computing system, folded in the dynamics of an integrated silicon microring resonator coupled to an external optical feedback. The performance of the network is evaluated on delayed digital tasks. Online-only&nbsp;seminar: https://uibuniversitat.zoom.us/j/87008849910 Url event:https://ifisc.uib-csic.es/en/events/seminars/experimental-investigation-of-a-microring-based-ti/

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PhD Thesis Defense on Friday, Feb 24, 2023 at 11:00
by semfis＠ifisc.uib-csic.es 17 Feb '23

17 Feb '23

PhD Thesis Defense on Friday Feb 24, 2023 at 11:00 Place: IFISC Seminar Room Title: Characterization and simulation of multipartite open quantum systems Speaker: Marco Cattaneo, Algorithmiq (Helsinki, Finland), PhD student of UIB (IFISC) and the University of Helsinki Abstract: Motivated by renewed studies on dissipative collective effect and by new discoveries about the features of noise in quantum computers, the interest in multipartite open quantum systems has recently risen. A dissipative collective effect may be defined as the coherent interference of the emissions (and/or absorptions) of many quantum particles interacting with external environments. Multipartite open quantum systems are open systems made of multiple subsystems, which can interact with each other and at the same time may be coupled to local and/or collective environments. The characterization and simulation of the dynamics of multipartite open quantum systems is the topic of this doctoral dissertation. The thesis addresses methodological questions, phenomenological predictions, and also presents an experimental implementation on a quantum computer. These contributions include the description and characterization of a general master equation for Markovian multipartite open quantum systems, and some new procedures for the analog and digital quantum simulation thereof.&nbsp; Jury:&nbsp;Anna Sanpera (UAB, Spain),&nbsp;Paolo Muratore (University of Helsinki, Finland), John Goold (Trinity College Dublin, Ireland) Supervisors:&nbsp; S. Maniscalco, R. Zambrini, G.L. Giorgi, M.A.C. Rossi Presential in the&nbsp; IFISC seminar room with parallel Zoom stream at https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09 &nbsp; &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/characterization-and-simulation-of-multipartite-op/

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PhD Thesis Defense on Friday, Feb 24, 2023 at 11:00
by semfis＠ifisc.uib-csic.es 13 Feb '23

13 Feb '23

PhD Thesis Defense on Friday Feb 24, 2023 at 11:00 Place: IFISC Seminar Room Title: Characterization and simulation of multipartite open quantum systems Speaker: Marco Cattaneo, Algorithmiq (Helsinki, Finland), PhD student of UIB (IFISC) and the University of Helsinki Abstract: Motivated by renewed studies on dissipative collective effect and by new discoveries about the features of noise in quantum computers, the interest in multipartite open quantum systems has recently risen. A dissipative collective effect may be defined as the coherent interference of the emissions (and/or absorptions) of many quantum particles interacting with external environments. Multipartite open quantum systems are open systems made of multiple subsystems, which can interact with each other and at the same time may be coupled to local and/or collective environments. The characterization and simulation of the dynamics of multipartite open quantum systems is the topic of this doctoral dissertation. The thesis addresses methodological questions, phenomenological predictions, and also presents an experimental implementation on a quantum computer. These contributions include the description and characterization of a general master equation for Markovian multipartite open quantum systems, and some new procedures for the analog and digital quantum simulation thereof.&nbsp; Jury:&nbsp;Anna Sanpera (UAB, Spain),&nbsp;Paolo Muratore (University of Helsinki, Finland), John Goold (Trinity College Dublin, Ireland) Supervisors:&nbsp; S. Maniscalco, R. Zambrini, G.L. Giorgi, M.A.C. Rossi Presential in the&nbsp; IFISC seminar room with parallel Zoom stream at https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09 &nbsp; &nbsp; Url event:https://ifisc.uib-csic.es/en/events/seminars/characterization-and-simulation-of-multipartite-op/

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Reminder: Master Thesis, TODAY - Friday, Feb 10, 2023 at 15:00
by semfis＠ifisc.uib-csic.es 10 Feb '23

10 Feb '23

Master Thesis on Friday Feb 10, 2023 at 15:00 Place: IFISC Seminar Room Title: Local probing of dynamical phase transitions by repeated partial information erasure Speaker: Hira Ali, IFISC Abstract: In this Master&#39;s Thesis, I will be discussing a new approach to probing the dynamical phases of an isolated quantum many-body system represented by a spin complex network. The protocol is based on local measurements of quantum observables and finding out if they display the convergence property or not. The results showed that the ability of a system to erase previous information with time depends critically on its dynamic phase. As a consequence, this probing method allows one to distinguish between ergodic and localized phases of matter.&nbsp; Supervisors: Gian Luca Giorgi and Roberta Zambrini Jury: Miguel C. Soriano, GIan Luca Giorgi, Gonzalo Manzano &nbsp; Presential at the IFISC seminar room, with parallel zoom streaming&nbsp; https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09 Url event:https://ifisc.uib-csic.es/en/events/seminars/local-probing-of-dynamical-phase-transitions-by-re/

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Reminder: Talk, TODAY - Thursday, Feb 09, 2023 at 12:00
by semfis＠ifisc.uib-csic.es 09 Feb '23

09 Feb '23

Talk on Thursday Feb 09, 2023 at 12:00 Place: IFISC Seminar Room Title: Information ecosystems: an ecological approach to computational social science Speaker: Violeta Calleja, IFISC (CSIC-UIB) Abstract: Abstract:&nbsp; Understanding human interactions in online communications is of paramount importance for our society. Alarming phenomena such as the spreading of fake news or the formation of echo chambers can emerge in unhealthy communication environments and, ultimately, undermine the democratic discourse. In this context, among many,&nbsp; two issues challenge the health of our information ecosystems: first, being able to identify their universal characteristics; and second, unveiling the individual drivers that give rise to collective attention. Here, following a recently proposed analogy between natural and information ecosystems, we explore these two challenges. We will present universal patterns that arise in very different discussions of online social networks,&nbsp; and we will continue explaining how our communication dynamics are shaped by the competition for attention in these online social networks and the strategies adopted by the users to maximize their visibility. Url event:https://ifisc.uib-csic.es/en/events/seminars/information-ecosystems-an-ecological-approach-to-c/

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Talk on Friday, Feb 10, 2023 at 15:00
by semfis＠ifisc.uib-csic.es 08 Feb '23

08 Feb '23

Talk on Friday Feb 10, 2023 at 15:00 Place: IFISC Seminar Room Title: Local probing of dynamical phase transitions by repeated partial information erasure Speaker: Hira Ali, IFISC Abstract: In this Master&#39;s Thesis, I will be discussing a new approach to probing the dynamical phases of an isolated quantum many-body system represented by a spin complex network. The protocol is based on local measurements of quantum observables and finding out if they display the convergence property or not. The results showed that the ability of a system to erase previous information with time depends critically on its dynamic phase. As a consequence, this probing method allows one to distinguish between ergodic and localized phases of matter.&nbsp; Supervisors: Gian Luca Giorgi and Roberta Zambrini Jury: Miguel C. Soriano, GIan Luca Giorgi, Gonzalo Manzano &nbsp; Presential at the IFISC seminar room, with parallel zoom streaming&nbsp; https://zoom.us/j/98286706234?pwd=bm1JUFVYcTJkaVl1VU55L0FiWDRIUT09 Url event:https://ifisc.uib-csic.es/en/events/seminars/local-probing-of-dynamical-phase-transitions-by-re/

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