11.01 Recent publications
F. Benatti, D. Chruscinski, S. Filippov. Tensor power of dynamical maps and positive versus completely positive divisibility. Phys. Rev. A 95, 012112 (2017), E-print arXiv:1610.04634 [quant-ph]
S. N. Filippov, K. Yu. Magadov. Positive tensor products of qubit maps and n-tensor-stable positive qubit maps. J. Phys. A: Math. Theor. 50, 055301 (2017), E-print arXiv:1604.01716 [quant-ph]
G.G. Amosov, S.N. Filippov. Spectral properties of reduced fermionic density operators and parity superselection rule. Quantum Information Processing 16, 1 (2017), doi:10.1007/s11128-016-1467-9, E-print: arXiv:1512.01828 [quant-ph]
11.12 Autumn conferences 2016
In autumn 2016 there were 2 fruitful conferences in my country:
59th MIPT Scientific conference, November 23-28, 2015, Moscow, Russia. My talk: Non-unitary maps and selective measurements in quantum tomography. Talks by students: (i) V.V. Frizen, S.N. Filippov, Two-qubit entangled states robust to amplitude damping noises, (ii) D.V. Kolobova, S.N. Filippov, Decomposition of non-unital qubit channels.
Ufa International Mathematical Conference, September 27-30, 2016, Ufa, Russia. My talk: Non-linear quantum dynamics induced by measurements. Talks by students: (i) I.A. Luchnikov, Dynamics of interacting spin chains in collisional model, (ii) K. Yu. Magadov, Entanglement-breaking fermionic quantum channels.
02.07 Summer conferences 2016
In summer 2016 I had a chance to attend three interesting conferences:
International Conference on Algebra, Analysis and Geometry, June 26 – July 2, 2016, Kazan, Russia. Talk: 2- and 3-tensor-stable positive qubit maps (presented by K.Yu. Magadov)
13th Central European Quantum Information Processing Workshop, June 16-19, 2016, Valtice, Czech Republic. Talk: Positive tensor products of qubit maps and 2-tensor-stable positive qubit maps [Presentation PDF, 4.63 MB]
48th Symposium on Mathematical Physics "Gorini-Kossakowski-Lindblad-Sudarshan Master Equation - 40 Years After", June 10-12, 2016, Torun, Poland. Poster: Non-linear dynamics induced by successive rank-r selective measurements (together with I.A. Luchnikov) [Poster PDF, 1.16 MB]
06.06 Visit in Turku
It was a pleasure to work for 2 weeks in the University of Turku and collaborate with Teiko Heinosaari on quantum incompatibility, and with Jyrki Piilo and Sabrina Maniscalco on visualization of k-P-divisible quantum dynamical maps.
18.04 Conference in Oxford 2016
There were lots of fruitful discussions at
International Workshop on "Reduced Density Matrices in Quantum Physics and Role of Fermionic Exchange Symmetry 2016," 12-15 April, 2016, Oxford, UK,
where I have presented a poster "Spectral properties of reduced fermionic density operators and parity superselection rule" [Poster PDF, 359kB]
07.04 Some recent publications
G.G. Amosov, S.N. Filippov. Spectral properties of reduced fermionic density operators and parity superselection rule. arXiv:1512.01828 [quant-ph]
S.N. Filippov, K.Yu. Magadov. Positive tensor products of qubit maps and 2-tensor-stable positive qubit maps. arXiv:1604.01716 [quant-ph]
31.12 Review of news for the year 2015
This web-page looks quite old fashioned, doesn't it?
You're right, it's getting older.
Here is the summary of 2015 news: my primary position is now in the Laboratory of quantum information theory at MIPT (at that web page you can find some recent activities related with my work), there were great conferences in Suzdal, Torun, and Lapland last year (the latter one should not be called conference, however!). Scientific work was spreaded, and now it is time to gather stones together. Teaching is all right, and I give a full course of Quantum mechanics as a lecturer in 2016.
You definitely have many questions, I hope to meet you in person to answer them.
22.10 New course of lectures "Quantum information channels"
Opening lecture will take place on Friday, Nov. 24, 2014, at 18:30 in lecture hall #115, Applied Mathematics Building MIPT.
Students of all years and faculties are welcome!
16.09 PPT-inducing, distillation-prohibiting, and entanglement-binding quantum channels
The new paper is avalable at arXiv:1409.4036 [quant-ph]
Entanglement degradation in open quantum systems is reviewed in the Choi-Jamiolkowski representation of linear maps. In addition to physical processes of entanglement dissociation and entanglement annihilation, we consider quantum dynamics transforming arbitrary input states into those that remain positive under partial transpose (PPT-inducing channels). Such evolutions form a convex subset of distillation-prohibiting channels. A relation between the above channels and entanglement-binding ones is clarified. An example of the distillation-prohibiting map Ф(х)Ф is given, where Ф is not entanglement binding.
20.07 RIA Novosti, Vesti 24, and MIPT press releases
RIA Novosti: Russian physicist invented a way to safely transmit quantum signals [in Russian]
Vesti 24: Teleportation may become real [in Russian]
03.07 PRA Rapid Communication and Editors' Suggestion
Our recent paper "Entanglement sensitivity to signal attenuation and amplification" has just been published in Physical Review A and selected as an Editors' Suggestion: http://journals.aps.org/pra/highlights
The text is available at the journal website and ArXiv
The paper's idea is briefly outlined here
10.06 CEQIP workshop 2014
11th Central European Quantum Information Processing Workshop was held in Znojmo, Czech Republic during the period of June 5-8, 2014. My talk "Dissociation and annihilation of multi-partite entanglement structures" was based on recent papers with Mario Ziman.
09.05 Entanglement sensitivity to signal attenuation and amplification
Recent paper written in collaboration with Mario Ziman is now available at arXiv:1405.1754 [quant-ph]
In this paper, we analyze general laws of continuous-variable entanglement dynamics during the deterministic attenuation and amplification of the physical signal carrying the entanglement. These processes are inevitably accompanied by noises, so we find fundamental limitations on noise intensities that destroy entanglement of gaussian and non-gaussian input states.
20.03 Our paper in Physica Scripta Highlights 2013
Our paper "Single-photon-added coherent states: estimation of parameters and fidelity of the optical homodyne detection" by S.N. Filippov, V.I. Man'ko, A.S. Coelho, A. Zavatta, and M. Bellini has been selected for Physica Scripta Highlights 2013!
The full text of the paper is now freely available without subscription until 31 December 2014: Physica Scripta T153, 014025 (2013)
16.03 Conference "Entanglement detection and quantification" (Bilbao, 2014)
The warm town of Bilbao welcomed physicists-"entanglers" in March 10-13 to provide a venue for extensive discussions of their favourite subject: phenomenon of quantum entanglement.
The abstract of my contribution is http://filippovsn.fizteh.ru/curriculumvitae.html/abstract_bilbao_2014.pdf.
09.02 XVII Conference "Quantum Information Processing" (QIP 2014)
23.12 Chemistry of quantum entanglement dynamics
Considering multipartite entanglement as a chemical compound opens a new view on the entanglement dissipative evolution. In fact, the particles of environment represent nothing else but the solvent in which the entanglement compound dissociates! The solvent can act on the whole compound (global quantum noise) or particular elements of the compound (local quantum noise). The differences between these two mechanisms are in the presense of clustering stages in the case of global noise, when particles reassemble to form almost equal bipartitions, tripartions, etc.
More info: S. N. Filippov, A. A. Melnikov, and M. Ziman. Dissociation and annihilation of multipartite entanglement structure in dissipative quantum dynamics. Phys. Rev. A 88, 062328 (2013), E-print arXiv:1310.4790 [quant-ph], Download <<PDF>>
30.09 Feasible coupling of two superconducting resonators by a single trapped atom
We present a theoretical proposal how to couple (selectively) microwave radiation in two superconducting resonators via the Raman effect for an ion trap.
More info about the idea: <<presentation [pdf, 530kB]>>
16.09 Revealing noise tolerance of quantum entanglement
Promising advances of quantum information technologies rely on the physical phenomenon of entanglement, a particular form of correlations exhibited by composite systems. After being created, the entanglement typically decreases due to unavoidable external noises. To fight with this undesirable effect, scientists have developed quaint methods to maintain correlations such as error correction and entanglement concentration protocols, etc. However, the nature can hardly be deceived, so if the noise level exceeds some fundamental limit, then the entanglement is lost without any chance to be resuscitated by local operations. In our paper [S.N. Filippov and M. Ziman, Bipartite entanglement-annihilating maps: Necessary and sufficient conditions, Phys. Rev. A 88, 032316 (2013)], we find the fundamental limit of such entanglement annihilation for any type of physical noisy evolution. The obtained result is crucial for determining the ultimate length of quantum communication lines.
Links to the paper: http://pra.aps.org/abstract/PRA/v88/i3/e032316 (restricted access), http://arxiv.org/abs/1306.6525 (free access)
09.06 10th Central European Quantum Information Processing Workshop
This year, CEQIP was held in Valtice, Czech Republic. The participants, organization, scientific and social activities (and the venue of course) created a very nice atmosphere reflected in some photos. Our team "Friday" (which sounds quite interesting in Finnish) took part in the cipher game and was the third to solve the final riddle. BTW, guess the solution!
As to science, you can look at our poster (it is self-explaining).
01.06 Joining the group of Miroslav Grajcar in Comenius University
Our collaborative work with the experimental group of Miroslav Grajcar has been started this year, and my official part-time job in Comenius University within the Integrated Quantum Information Technology (IQIT) project began on June 1, 2013.
More information about the project is here.
17.12 Joining the group of Research Center for Quantum Information
From Dec 17, 2012 I took a sabbatical leave from MIPT to do research in the Research Center for Quantum Information, Institute of Physics, Slovak Academy of Sciences http://www.quniverse.sk/
My present address: RCQI, FU SAV, Dubravska cesta 9, 84511 Bratislava, Slovakia
Telephone: +421 2 20910701
International Conference "Micro- and NanoElectronics - 2012" was held recently in Moscow Region (October 1-5, 2012).
My talk entitled "Entanglement-annihilating quantum dynamical processes" was presented at the extended session "Quantum Informatics" and the presentation is available at http://filippovsn.fizteh.ru/curriculumvitae.html/Filippov_ICMNE_2012.pdf.
25.07 Summer School "Applications of Quantum Mechanics II" (Cuernavaca, Mexico, July 16-27, 2012)
Course of lectures "Quantum technologies":
13.07 CEWQO 2012
19th Central European Workshop on Quantum Optics was held on July 2-6, 2012, in Sinaia, Romania
Postconference facebook group is http://www.facebook.com/groups/257669631015857/
My photos are available at http://filippovsn.fizteh.ru/albums/conferences/cewqo2012.html
The presentation of my talk entitled "Optical homodyne tomography: operational use of data and evaluation of errors" is available at http://filippovsn.fizteh.ru/curriculumvitae.html/Filippov-CEWQO-2012.pdf
02.06 Recent articles in Physical Review A
Two articles have appeared nearly simultaneously:
25.05 PhD defense
On May 25, 2012 I successfully defended my PhD thesis entitled "Quantum states and dynamics of spin systems and electromagnetic field in the tomographic-probability representation."
I would like to sincerely thank all my friends, relatives, and colleagues for their kind help and confidence!
17.02 Collaboration with Quantum Optics group of the University of Rostock
Our collaboration is devoted to studying quantum properties of electromagnetic field and related subjects under supervision of Prof. Vogel.
Presentation of my talk "Tomographic approach to quantum states of electromagnetic radiation and spin states" is available at http://filippovsn.fizteh.ru/curriculumvitae.html/Rostock_2012.ppsx [5.73 Mb]
Some photos of my visit to Rostock (Jan-Feb 2012) are available at http://filippovsn.fizteh.ru/albums/conferences/rostock2012.html
03.12 Star product and ordered moments of photon creation and annihilation operators
This article is to be printed in 2012 but it is already available online at http://iopscience.iop.org/1751-8121/45/1/015305/.
Artilce details: S N Filippov and V I Man'ko 2012 J. Phys. A: Math. Theor. 45 015305
28.11 MIPT Conference 2011
This autumn saw the 60th birthday of my Alma Mater and a Conference devoted to such an occasion also.
My contributions to the Conference include the following two talks:
Talk #1: Quantum dynamics of ordered moments of creation and annihilation photon operators within the star-product formalism <<abstract [pdf, 156kB, in Russian]>> <<presentation[pdf, 2.40MB, in Russian]>>
Talk #2: Positive and completely positive maps in the problem of entanglement-breaking and entanglement-annihilating channels <<abstract [pdf, 150kB, in Russian]>> <<presentation [pdf, 1.72MB, in Russian]>>
10.11 Effect of image charge on double quantum dot evolution
This article is written in collaboration with V. Vyurkov and L. Fedichkin and is published in Physica E: Low-dimensional Systems and Nanostructures, 44, 501-505 (2011)
18.10 Local two-qubit entanglement-annihilating channels
Article is written in collaboration with Tomas Rybara and Mario Zimana,b, deals with rather interesting properties of two-qubit channels and is now available at arXiv:1110.3757v1 [quant-ph]
a Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia (RCQI)
b Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
15.09 Measuring microwave quantum states: Tomogram and moments
Article has been published online: Physical Review A 84, 033827 (2011)
31.08 Summer Physics School "Modern Statistical Methods in Quantum Information Processing"
This wonderful event was held in Bad Honnef, Germany. Photos are in here. Also I was given a certificate [312kB].
31.08 Canadian Summer School on Quantum Information 2011: exam results
It is my pleasure to inform that the final exam at CSSQI'2011 has been successfully passed with A.
Link to a certificate [pdf, 90kB, in French].
16.06 Canadian Student Conference on Quantum Information 2011
Talk: MUBs and SIC-POVMs in view of star-product formalism and tomographic-probability representation of qudits
Presentation is available here [pdf, 498kB]
14.05 Quantum teleportation & Department of Theoretical Physics on TV
A few seconds of the Department of Theoretical Physics in weekly teleprogram 'Friday' [in Russian]
30.03 Optical tomography of Fock state superpositions
The appearance of this Comment is aimed at 'shifting paradigm' of representing quantum optics measurements.
Article details: Physica Scripta 83 (2011) 058101
Link to Publisher: http://iopscience.iop.org/1402-4896/83/5/058101/
26.02 Article dealing with MUB-quantization scheme has appeared
S.N. Filippov, V.I. Man'ko: Mutually unbiased bases: tomography of spinstates and star-product scheme, Physica Scripta, T143, 014010 (2011)
(BTW, available free for everybody at Publisher's site for 30 days)
A concise version of the article is also available online at arXiv:1008.2675v1 [quant-ph]
15.02 Contests 2010
It is my pleasure to inform you about the recent awards by
1) Russian Science Support Foundation
2) Dynasty Foundation
29.11 Conference autumn 2010
This fall was full of different conferences on a wide range of topics concerning more or less my scientific interests. It was my pleasure to take part and give reports at the following ones:
- International Conference on Quantum Information and Computation
- 6th International SemOI Workshop "Nanoscaled Semiconductor-on-Insulator Materials, Sensors, and Devices"
- III Nanotechnology International Forum RusNanoTech 2010
- 53rd Conference of Moscow Institute of Physics and Technology 'Modern problems of fundamental and applied sciences'
The detailed information including abstracts, posters, and presentations is available in section Curriculam Vitae.
10.10 Distances between quantum states in the tomographic-probability representation
This is another long-awaited article which has appeared recently (a year after submission). It is published in a special issue of Physica Scripta devoted to 16th Central European Workshop on Quantum Optics held in May 2009 in Turku, Finland.
Article details: S.N. Filippov, V.I. Man'ko: Distances between quantum states in the tomographic-probability representation, Physica Scripta T140, 014043 (2010)
09.10 2 years and 8 months of awaiting for an article in "Proceedings of MIPT" gone!
It is very nice when something reminds about the work you have done long time ago. Indeed, I am very proud to be a co-author of the article in the journal "Proceedings of MIPT" which has been peer reviewed, processed, and finally published 2 years and 8 months after submission. This paper is based on my Bachelor Thesis and deals with infrared photodiodes. To be exact, the title is "Investigation of charge transfer mechanisms in HgCdTe photodiodes". I must apologize to foreigners because the article is written in Russian and is not translated into English. However, readers (if any) who are interested in this work can approach me with a request for translation without hesitation. If this is the case, I will do my best to get them acquainted with the results we have obtained.
I am very grateful to the supervisor of my Bachelor research, Prof. Konstantin Olegovich Boltar', and greatly appreciate his assistance in theoretical studying of narrow-band semiconductors and, certainly, many experimental skills that I learnt during 2006-2007 (cryostat technique and data processing). So this article is in honour of Prof. Boltar'!
For detailed information about the article and abstract click the title of this piece of news.
The article is available here [pdf, 771kB].
21.08 Mutually unbiased bases: tomography of spin states and star-product scheme
In this article, a star-product scheme for a full set of mutually unbiased bases is established.
Abstract. Mutually unbiased bases (MUBs) are considered within the framework of a generic star-product scheme. We rederive that a full set of MUBs is adequate for a spin tomography, i.e. knowledge of all probabilities to find a system in each MUB-state is enough for a state reconstruction. Extending the ideas of the tomographic-probability representation and the star-product scheme to MUB-tomography, dequantizer and quantizer operators for MUB-symbols of spin states and operators are introduced, ordinary and dual star-product kernels are found. Since MUB-projectors are to obey specific rules of the star-product scheme, we reveal the Lie algebraic structure of MUB-projectors and derive new relations on triple- and four-products of MUB-projectors. Example of qubits is considered in detail. MUB-tomography by means of Stern-Gerlach apparatus is discussed.
Comments are welcome!
Article is available online at http://arxiv.org/abs/1008.2675
21.08 MuSR method and tomographic probability representation of spin states
This July, an article written by researches of the Department of Theoretical Physics appeared. We grieve that our co-author V.N. Gorelkin will not see it published.
Article details: Yu. M. Belousov, S. N. Filippov, V. N. Gorelkin, V. I. Man'ko, MuSR method and tomographic probability representation of spin states, arXiv:1007.3814v1 [quant-ph]
Article is available online at http://arxiv.org/abs/1007.3814
21.07 Article entitled "SIC-POVM and probability representation of quantum mechanics" has appeared in J. Russ. Laser Res.
This is to inform you that our article entitled "Symmetric informationally complete positive operator valued measure and probability representation of quantum mechanics" by Vladimir I. Man'ko and me has been published in Journal of Russian Laser Research 31(3), 211-231 (2010) <<link>>
Your comments are kindly welcome!
15.07 Quantum computing based on space states without charge transfer
This article is a result of my work in the Institute of Physics and Technology RAS during my master project. In the article, special attention is paid to all necessary procedures for Quantum Computer to operate: qubit structure, initialization, realization of one- and two-qubit operations, 'fighting' with decoherence, and read-out. Qubit structure and encoding of quantum information is quite unusual and we hope you will find them interesting.
Article details: V. Vyurkov, S. Filippov, and L. Gorelik, Quantum computing based on space states without charge transfer, Physics Letters A 374 (2010), pp. 3285-3291.
Link to the article: http://dx.doi.org/10.1016/j.physleta.2010.06.023
08.07 1st International Scientific School for Young Researches and Teachers "Applied Mathematics and Physics: from Fundamental Investigations to Innovations"
This July in Dolgoprudny, Russia, our Institute is hosting the 1st International Scientific School for Young Researches and Teachers "Applied Mathematics and Physics: from Fundamental Investigations to Innovations." Within the framework of section "Teoretical and Mathematical Physics," I was hornered to give a talk entitled "Probability representation and tomography of spin states". The presentation is available here.
27.06 Time evolution of two interacting charge qubits: entanglement and mean-field approach
I am glad to inform you that article entitled "Time evolution of two interacting charge qubits: entanglement and mean-field approach" by Sergey Filippov and Vladimir Vyurkov has finally appeared in the journal Quantum Computers and Computing 9(1), 60-65 (2009). This work was done during my Master Project in the Institute of Physics and Technology of the Russian Academy of Sciences (2007-2009). The full text is available (free access) at the publisher site.
18.06 17th Central European Workshop on Quantum Optics (CEWQO'2010)
It was a great honour for me to take part in the 17th Central European Workshop on Quantum Optics held on June 6-11 in St. Andrews, Scotland, UK. At the conference, I have presented a poster "Inverse spin-s portrait method: Representation of qudit states by probability vectors and Spin tomography" by me and Prof. Man'ko. If you are interested in it, you can click <<abstract>> and <<poster>>.
27.05 Philosophy of Science: Quantum Information Theory
It is my pleasure to inform you that my final exam on philosophy of science has been passed successfully. My project on this subject concerns the history and philosophical aspects of Quantum Information Theory and is available here [pdf,419kB,in Russian].
26.05 "Last Ring" Day of the year 2010 in Licee #11 "PhysTech"
Once a year there is a moment when I and my schoolpupils have to say goodbye to each other. I must admit that this Day is joyful and sad at the same time. But "life is life", so let us keep nice memories of those two years in our mind!
25.05 Symmetric informationally complete positive operator valued measure and probability representation of quantum mechanics
May saw a new article dealing with symmetric informationally complete positive operator valued measure (SIC-POVM) and its relation to the probability representation of quantum mechanics. Article is available online at http://arxiv.org/abs/1005.4091
17.04 Final English exam at the Postgraduate school.
I am happy to inform you that this rather difficult (for me) exam was successfully passed. Bingo! See a link to the presentation inside this piece of news.
04.02 Wolfram Demonstrations Project: Qubit and Qutrit States in the Probability Space
.New demonstrations give some insight to comprehend subsets of qubit and qutrit states in the probability space. Demonstrations enable you to change parameters and trace the change of the investegated object.
Qubits (spin = 1/2):http://demonstrations.wolfram.com/RepresentationOfQubitStatesByProbabilityVectors/
Qutrits (spin = 1): http://demonstrations.wolfram.com/QutritStatesAsProbabilityVectors/
27.01 Inverse Spin-S Portrait and Representation of Qudit States by Single Probability Vectors
.January saw a new article devoted to bijective mapping of qudit states onto single probability vectors. It is available at LANL Preprint http://arxiv.org/abs/1001.4813
23.12 Probability representation and quantumness tests for qudits and two-mode light states.
The article 'Probability representation and quantumness tests for qudits and two-mode light states' was published in Journal of Russian Laser Research 30 (2009). This article is based on the contribution to the 11th International Conference on Squeezed States and Uncertainty Relations held in Olomouc, Czech Republic, June 2009.
28.11 MIPT Conference.
My contribution to the 52th Scientific Conference "Modern problems of fundamental and applied sciences" organized by the Moscow Institute of Physics and Technology. Abstracts of talks and presentations are presented.