ITP-quantumseminare

itp-quantumseminare@lists.phys.ethz.ch

1 participants
1357 discussions

meeting today E41.1 @ 3:30 pm
by Joe Renes 17 Sep '18

17 Sep '18

Hi all, Today we'll have a brief meeting to start off the semester. I'll tell you about an uncertainty relation I'd like to prove; it involves min entropies and could be applied to quantum error correction. Mainly we need to determine if 3:30 Monday's is a good time for the meeting this semester. Best, -joe

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talk today by Karl Mayer: HIT E41.1 @ 2pm
by Joe Renes 14 Sep '18

14 Sep '18

Hi all, today we have a visitor, Karl Mayer, from Manny Knill's group at the University of Colorado. Karl will give a ~1/2 hour talk about his research on tomography at 2pm in E41.1. See below for the title and abstract. Best, -joe Paper: https://arxiv.org/abs/1805.04491 Title: Quantum Process Fidelity Bounds from Sets of Input States Abstract: We investigate the problem of bounding the quantum process fidelity given bounds on the fidelities between target states and the action of a process on a set of pure input states. We formulate the problem as a semidefinite program and prove convexity of the minimum process fidelity as a function of the errors on the output states. We characterize the conditions required to uniquely determine a process in the case of no errors, and derive a lower bound on its fidelity in the limit of small errors for any set of input states satisfying these conditions. We then consider sets of input states whose one-dimensional projectors form a symmetric positive operator-valued measure (POVM). We prove that for such sets the minimum fidelity is bounded by a linear function of the average output state error. The minimal non-orthogonal symmetric POVM contains d+1 states, where d is the Hilbert space dimension. Our bounds applied to these states provide an efficient method for estimating the process fidelity without the use of full process tomography.

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no meeting today --- holiday
by Joe Renes 10 Sep '18

10 Sep '18

Hi all, no meeting today due to the holiday: https://www.knabenschiessen.ch/ -joe

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talk by Tony Short: Thursday 11:00 HIT K52
by Joe Renes 05 Sep '18

05 Sep '18

Hi all, we'll have a special talk tomorrow by Tony Short from Bristol. It's at 11 in K52; here's the title and abstract: Title: Indefinite causal order via post-selection Abstract: We consider how post-selection can be used to generate indefinite causal structures, which cannot be explained by any fixed (or random) temporal ordering, and the connection to process matrices and backwards in time signalling. Based on arXiv:1701.08638 and arXiv:1708.00669. Best, -joe

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today's talk K52 @ 15:30
by Joe Renes 03 Sep '18

03 Sep '18

Hi all, today we'll hear from Luca Mondada on his semester project with Raban. Note that we're in K52 today, as there's a small conference on topological order taking place on the ground floor. Best, -joe

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no meeting today
by Joe Renes 27 Aug '18

27 Aug '18

Hi all, no meeting today (for those following the group calendar, we had to move today's planned talk due to a scheduling error). Best, -joe

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today's group meeting E41.1 @ 15:30
by Joe Renes 20 Aug '18

20 Aug '18

Hi all, today we'll hear from Markus Müller, who's visiting from Vienna. I believe he'll talk about this paper: https://arxiv.org/abs/1712.01816. Best, -joe

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talk by Marco Tomamichel tomorrow: 14:30, location TBA
by Joe Renes 17 Aug '18

17 Aug '18

Hi all, tomorrow Marco will tell us about his recent preprint arXiv:1807.01852 <http://arxiv.org/abs/1807.01852>, "Efficient online quantum state estimation using a matrix-exponentiated gradient method". Current plan is for 14:30, but may change if there are massive conflicts. Best, -joe

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today's meeting E41.1 @ 15:30
by Joe Renes 13 Aug '18

13 Aug '18

Hi all, today we will hear from Emanuel Malvetti, who is doing a semester project with Raban. Best, -joe

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today's meeting E41.1 @ 15:30
by Joe Renes 06 Aug '18

06 Aug '18

Hi all, today we'll hear from Johannes Fankhauser on his master's thesis project. Best, -joe

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ITP-quantumseminare