7 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 7 / 7
Yayın Behavior of quantum fisher information of bell pairs under decoherence channels(Polish Acad Sciences Inst Physics, 2014-02) Özaydın, Fatih; Altıntaş, Azmi Ali; Buğu, Sinan; Yeşilyurt, CanQuantum Fisher information has recently been an essential tool for analyzing the phase sensitivity of the quantum states in various quantum tasks, requiring high precision, such as quantum clock synchronization, positioning and many applications which include quantum interferometers. Due to the interactions with the environment, all quantum systems are subject to various decoherence effects. Therefore the research on quantum Fisher information under decoherence has been recently attracting more attention. In this work, analyzing the quantum Fisher information, we study the phase sensitivity of bipartite quantum correlations, in particular four Bell pairs amplitude damping channels. For a specific Bell state we arrive at similar results of Greenberger-Horne-Zeilinger (GHZ) states (as expected). For the other three Bell states, we present our results which point the interesting behavior of quantum Fisher information with respect to the decoherence rate. We also find the regions where the quantum Fisher information exhibits discontinuities.Yayın Surpassing the classical limit in magic square game with distant quantum dots coupled to optical cavities(Nature Research, 2020-12-17) Buğu, Sinan; Özaydın, Fatih; Kodera, TetsuoThe emergence of quantum technologies is heating up the debate on quantum supremacy, usually focusing on the feasibility of looking good on paper algorithms in realistic settings, due to the vulnerability of quantum systems to myriad sources of noise. In this vein, an interesting example of quantum pseudo-telepathy games that quantum mechanical resources can theoretically outperform classical resources is the Magic Square game (MSG), in which two players play against a referee. Due to noise, however, the unit winning probability of the players can drop well below the classical limit. Here, we propose a timely and unprecedented experimental setup for quantum computation with quantum dots inside optical cavities, along with ancillary photons for realizing interactions between distant dots to implement the MSG. Considering various physical imperfections of our setup, we first show that the MSG can be implemented with the current technology, outperforming the classical resources under realistic conditions. Next, we show that our work gives rise to a new version of the game. That is, if the referee has information on the physical realization and strategy of the players, he can bias the game through filtered randomness, and increase his winning probability. We believe our work contributes to not only quantum game theory, but also quantum computing with quantum dots.Yayın Constructing quantum logic gates using q-deformed harmonic oscillator algebras(Springer, 2014-04) Altıntaş, Azmi Ali; Özaydın, Fatih; Yeşilyurt, Can; Buğu, Sinan; Arık, MetinWe study two-level q-deformed angular momentum states, and using q-deformed harmonic oscillators, we provide a framework for constructing qubits and quantum gates. We also present the construction of some basic one-qubit and two-qubit quantum logic gates.Yayın İki qubit’lik kuantum haberleşme ağlarının eş zamanlılık donanıklık ölçütü ile kuantum Fisher bilgisinin analizi(IEEE, 2014-06-12) Erol, Volkan; Buğu, Sinan; Özaydın, Fatih; Altıntaş, Azmi AliKuantum dolanıklık, kuantum haberleşme mühendisliğinin en temel kavramlarından biridir. Kuantum sistemlerin dolanıklık ölçütlerine göre sıralanması günümüzde oldukça çok çalışılan konulardan birisidir. İki parçacıklı iki seviyeli sistemlerin (qubit) sıralaması konusu, çok bilinen Eş Zamanlılık (Concurrence), Negatiflik (Negativity) ve Dolanıklığın Göreceli Entropisi (REE) ölçütlerine göre çeşitli araştırmacılar tarafından çalışılmıştır[1-5]. Biz bu çalışmada, iki qubit kuantum sistemlerin sıralamasını Kuantum Fisher Bilgisi ve Eş Zamanlılık dolanıklık ölçütünü karşılaştıracak şekilde analiz etmekteyiz. Çalışma özelinde, bin adet rastgele türetilmiş iki qubit sistemin Eş Zamanlılık değerleri hesaplanmakta; elde ettiğimiz bu sonuçların iki qubit sistemlerde Kuantum Fisher Bilgisi ile karşılaştırılması yapılmakta ve aralarındaki ilginç farklar gözlemlenmektedir.Yayın Analysis of entanglement measures and LOCC maximized quantum fisher information of general two qubit systems(Nature Publishing Group, 2014-06-24) Erol, Volkan; Özaydın, Fatih; Altıntaş, Azmi AliEntanglement has been studied extensively for unveiling the mysteries of non-classical correlations between quantum systems. In the bipartite case, there are well known measures for quantifying entanglement such as concurrence, relative entropy of entanglement (REE) and negativity, which cannot be increased via local operations. It was found that for sets of non-maximally entangled states of two qubits, comparing these entanglement measures may lead to different entanglement orderings of the states. On the other hand, although it is not an entanglement measure and not monotonic under local operations, due to its ability of detecting multipartite entanglement, quantum Fisher information (QFI) has recently received an intense attraction generally with entanglement in the focus. In this work, we revisit the state ordering problem of general two qubit states. Generating a thousand random quantum states and performing an optimization based on local general rotations of each qubit, we calculate the maximal QFI for each state. We analyze the maximized QFI in comparison with concurrence, REE and negativity and obtain new state orderings. We show that there are pairs of states having equal maximized QFI but different values for concurrence, REE and negativity and vice versa.Yayın Kübit-Kütrit kuantum haberleşme sistemleri için negatiflik ve dolanıklığın göreceli entropisi ölçütlerinin analizi(IEEE, 2015-06-19) Erol, Volkan; Özaydın, Fatih; Altıntaş, Azmi AliKuantum Bilgi Teorisi ve Kuantum Hesaplama konuları geleceğin bilgisayar teknolojisi olarak nitelendirilen ve çok yüksek hızlarda işlem yapacak olması öngörülen Kuantum Bilgisayarlarının teorik temelini oluşturan oldukça sıcak çalışma alanlarıdır. Kuantum Bilgisayarlarında bilginin taşınacağı birim kübit olarak nitelendirilse de, bazı problemler için bu birimlerin üç seviye (trinary) olan kütritlerce kurgulanabileceği teorik olarak gösterilmiştir. Bu çalışma kapsamında, kübit-kütrit Kuantum Haberleşme Sistemlerinin dolanıklıklığını ölçmek için kullanılan Negatiflik ve Dolanıklığın Göreceli Entropisi ölçütlerinin karşılaştırmalı analizi yapılmıştır. Bu bağlamda, rastgele türetilmiş 1000 adet kübit-kütrit sistem durumlarının adı geçen ölçütleri hesaplanmış ve bu değerler sistem durumlarının sıralanması amacıyla karşılaştırılmıştır. Yapılan analiz kapsamında sistem durumlarının sıralaması problemi açısından oldukça ilginç sonuçlar gözlemlenmiştir.Yayın Prisoners’ dilemma in a spatially separated system based on spin–photon interactions(MDPI, 2022-09) Altıntaş, Azmi Ali; Özaydın, Fatih; Bayındır, Cihan; Bayrakçı, VeyselHaving access to ideal quantum mechanical resources, the prisoners’ dilemma can be ceased. Here, we propose a distributed quantum circuit to allow spatially separated prisoners to play the prisoners’ dilemma game. Decomposing the circuit into controlled-Z and single-qubit gates only, we design a corresponding spin–photon-interaction-based physical setup within the reach of current technology. In our setup, spins are considered to be the players’ logical qubits, which can be realized via nitrogen-vacancy centers in diamond or quantum dots coupled to optical cavities, and the game is played via a flying photon realizing logic operations by interacting with the spatially separated optical cavities to which the spin qubits are coupled. We also analyze the effect of the imperfect realization of two-qubit gates on the game, and discuss the revival of the dilemma and the emergence of new Nash equilibria.
