Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session A46: Entanglement in Open Quantum SystemsFocus

Hide Abstracts 
Sponsoring Units: GQI GSNP Chair: Stephanie Wehner, Delft University of Technology Room: 393 
Monday, March 13, 2017 8:00AM  8:36AM 
A46.00001: Fluctuation relations and Maxwell's demon in a circuit QED setup Invited Speaker: Yasunobu Nakamura The recent progress in information thermodynamics has resolved the paradox of Maxwell's demon and clarified the relationship between the information and the entropy [1]. Its extension to quantum mechanical systems has also attracted much interest, and experimental demonstrations are awaited. Circuit QED systems offer the following tools suitable for investigating the properties of a quantum system coupled with a controlled environment: (i) a wellcontrolled qubit with a long coherence time, (ii) dispersive readout allowing highfidelity quantum nondemolition measurement, and (iii) fast feedback control. We first apply the socalled twomeasurement protocol (TMP) to a superconducting transmon qubit in a microwave cavity and study how the decoherence affects the nonequilibrium thermodynamic relations [2]. Next, we implement Maxwell's demon in the circuit QED system by introducing a feedback loop and confirm the fluctuation relation including the effect of the information obtained in the feedback process [3]. These results constitute a first step towards quantum thermodynamics in circuit QED systems. [1] J. M. R. Parrondo, J. M. Horowitz, and T. Sagawa, Nature Phys. 11, 131 (2015). [2] J. Pekola {\it et al.}, Phys. Rev. E 91, 062109 (2015). [3] K. Funo, Y. Murashita, and M. Ueda, New J. Phys. 17, 075005 (2015). [Preview Abstract] 
Monday, March 13, 2017 8:36AM  8:48AM 
A46.00002: Quantum resource theory of nonstabilizer states in the oneshot regime Mehdi Ahmadi, Hoan Dang, Gilad Gour, Barry Sanders Universal quantum computing is known to be impossible using only stabilizer states and stabilizer operations. However, addition of nonstabilizer states (also known as magic states) to quantum circuits enables us to achieve universality. The resource theory of nonstablizer states aims at quantifying the usefulness of nonstabilizer states. Here, we focus on a fundamental question in this resource theory in the so called singleshot regime: Given two resource states, is there a free quantum channel that will (approximately or exactly) convert one to the other?. To provide an answer, we phrase the question as a semidefinite program with constraints on the Choi matrix of the corresponding channel. Then, we use the semidefinite version of the Farkas lemma to derive the necessary and sufficient conditions for the conversion between two arbitrary resource states via a free quantum channel.~ [Preview Abstract] 
Monday, March 13, 2017 8:48AM  9:00AM 
A46.00003: Characterization of the propagation of local observables under matchgate evolution Adrian Chapman, Akimasa Miyake We present a classically efficient algorithm to exactly propagate the support of a local observable under Heisenberg evolution by a nearestneighbor matchgate circuit. Support propagation is quantified by the LiebRobinson commutator norm, whose time evolution admits an efficient classical simulation by our algorithm. This is surprising in light of the fact that the Heisenberg evolution of the local observable itself cannot even be stored efficiently by a classical computer in the worst case. We apply our result to the study of propagation through a spin chain in the presence of locally fluctuating disorder and examine several interesting features of our numerical results. [Preview Abstract] 
Monday, March 13, 2017 9:00AM  9:12AM 
A46.00004: Quantum Entanglement in JaynesCummings Model and its applications Samina Masood Quantum entanglement in JaynesCummings model with two atoms and two photons have been studied. This study is extended to larger systems with more atoms and more photons. This quantum entanglement can affect~the cavity losses and may be applied to quantum computers or quantum information systems. [Preview Abstract] 
Monday, March 13, 2017 9:12AM  9:24AM 
A46.00005: Fast Entanglement Establishment via Local Dynamics for Quantum Repeater Networks Laszlo Gyongyosi, Sandor Imre Quantum entanglement is a necessity for future quantum communication networks, quantum internet, and longdistance quantum key distribution. The current approaches of entanglement distribution require highdelay entanglement transmission, entanglement swapping to extend the range of entanglement, highcost entanglement purification, and longlived quantum memories. We introduce a fundamental protocol for establishing entanglement in quantum communication networks. The proposed scheme does not require entanglement transmission between the nodes, highcost entanglement swapping, entanglement purification, or longlived quantum memories. The protocol reliably establishes a maximally entangled system between the remote nodes via dynamics generated by local Hamiltonians. The method eliminates the main drawbacks of current schemes allowing fast entanglement establishment with a minimized delay. Our solution provides a fundamental method for future longdistance quantum key distribution, quantum repeater networks, quantum internet, and quantumnetworking protocols. [Preview Abstract] 
Monday, March 13, 2017 9:24AM  9:36AM 
A46.00006: Entanglement control in two interacting qubits coupled to a radiation field Gehad Sadiek, M. Sebaweh Abdullah, Wiam AlDrees The interaction between a quantum system and a bosonic field has been one of the central problems in physics. It manifests itself in many different systems of interest such as atoms, ions, molecules and quantum dots coupled to radiation fields in cavity QED, which all are of special interest for quantum information processing. The coupling between a twolevel quantum system and a bosonic field is best described by the Rabi model (1936), which is not analytically solvable. Latter, the Jaynescummings model (JCM)(1963) presented a solution using the rotated wave approximation. Since then, most of the investigations have focused on the coupling between multiple quantum systems at one hand and radiation fields at the other hand, ignoring the possible coupling between the quantum systems themselves. We consider two interacting twolevel quantum systems (qubits) coupled to a singlemode quantized field, where we present an analytic solution for the problem. We show the impact of the coupling between the two quantum systems on the different properties of the composite system, such as the entanglement and the collapserevival phenomenon. The interplay between the qubitqubit coupling and the qubitradiation coupling is investigated thoroughly. [Preview Abstract] 
Monday, March 13, 2017 9:36AM  9:48AM 
A46.00007: Entanglementassisted state discrimination and entanglement preservation \"{O}zen\c{c} G\"{u}ng\"{o}r, Sadi Turgut In this study, the following scenario is considered: there are two qubits possessed by two parties at different locations. Qubits have been prepared in one of a maximum of four, mutuallyorthogonal, entangled states and the parties wish to distinguish between the states by using local operations and classical communication. Although in general it is not possible to distinguish between four arbitrary states, the parties can spend some preshared entanglement to achieve perfect discrimination between four qubit states and can also preserve the entanglement of the states after discrimination. This is shown by employing the theory of majorization and the connections between entanglement transformations and state discrimination protocols. References: \"{O}. G\"{u}ng\"{o}r, S. Turgut, "Entanglementassisted state discrimination and entanglement preservation," Physical Review A 94, 032330 (2016) and references in. [Preview Abstract] 
Monday, March 13, 2017 9:48AM  10:00AM 
A46.00008: MomentumSpace Entanglement and Loschmidt Echo in Luttinger Liquids after a Quantum Quench Rex Lundgren, Balázs Dóra, Mark Selover, Frank Pollmann Luttinger liquids (LLs) arise by coupling left and rightmoving particles through interactions in one dimension. This most natural partitioning of LLs is investigated by the momentumspace entanglement after a quantum quench using analytical and numerical methods. We show that the momentumspace entanglement spectrum of a LL possesses many universal features both in equilibrium and after a quantum quench. The largest entanglement eigenvalue is identical to the Loschmidt echo, i.e., the overlap of the disentangled and final wave functions of the system. The second largest eigenvalue is the overlap of the first excited state of the disentangled system with zero total momentum and the final wave function. The entanglement gap is universal both in equilibrium and after a quantum quench. The momentumspace entanglement entropy is always extensive and saturates fast to a time independent value after the quench, in sharp contrast to a spatial bipartitioning. Ref: Phys. Rev. Lett. 117, 010603 (2016) [Preview Abstract] 
Monday, March 13, 2017 10:00AM  10:12AM 
A46.00009: Universal structure of volumelaw entanglement in isolated quantum systems Sho Sugiura, Hiroyuki Fujita, Yuya Nakagawa, Masataka Watanabe In broad classes of pure quantum states, their entanglements increases in propotional to their subsystem size. This property is called the volumelaw of entanglement. For example, excited energy eigenstates and states after quantum quenches obey the volumelaw. However, when the subsystem size is close to the half of the size of the system, the entanglement deviates from the volumelaw. We reveal its general behavior. In this talk, We focus on Renyi entropies, especially, 2nd Renyi entropy. We will analyze the volumelaw of Renyi entropies using the thermal pure quantum states and obtain their exact behaviors. Our results are so universal that entanglement structures in many kinds of equilibrium states are explained by it. [Preview Abstract] 
Monday, March 13, 2017 10:12AM  10:24AM 
A46.00010: Quantum Fisher Information as a function response to a weak external perturbation Fernando Rojas, Jesus A. Maytorena The quantum fisher information (QFI) is known as a good indicator of entanglement in a multipartite systems. In this work we show that it can be treated as an induced response to an external field, in the same spirit of the usual linear response theory, with respect to a linear combination of observables of each subsystem. We derive an expression for a corresponding linear dynamical susceptibilitywhich contains relevant information about entanglement properties of a multipartite system. This approach is applied to investigate the hybrid entanglement in the driven JaynesCummings model. The Fisher susceptibility response function is obtained and allows us to characterize the changes on quantum correlations between the qubit and photon states, in terms of the driving frequency, atomfield coupling, and temperature. [Preview Abstract] 
Monday, March 13, 2017 10:24AM  10:36AM 
A46.00011: N multipartite GHZ states in quantum networks Valentina Caprara Vivoli, Stephanie Wehner Nowadays progress in experimental quantum physics has brought to a significant control on systems like nitrogenvacancy centres, ion traps, and superconducting qubit clusters. These systems can constitute the key cells of future quantum networks, where tasks like quantum communication at large scale and quantum cryptography can be achieved. It is, though, still not clear which approaches can be used to generate such entanglement at large distances using only local operations on or between at most two adjacent nodes. Here, we analyse three protocols that are able to generate genuine multipartite entanglement between an arbitrary large number of parties. In particular, we focus on the generation of the GreenbergerHorneZeilinger state. Moreover, the performances of the three methods are numerically compared in the scenario of a decoherence model both in terms of fidelity and entanglement generation rate. [Preview Abstract] 
Monday, March 13, 2017 10:36AM  10:48AM 
A46.00012: Quantum Speed Limit in the Thermal SpinBoson System with and without Tunneling. shahram dehdashti, M Bagheri Harouni, a mahdifar, H wang, Z xu, B Mirza, J Shen, H Chen In this study, we study the spinbosonic model, with and without tunneling terms, in detail. The spinbosonic model without tunneling is studied by using the thermofield dynamics approach. By considering temperature, we show that states of the environment, while they become entangled with system, approach thermal coherent states with different phases. In addition, by considering the tunneling term, we study the interplay of the environmental cutoff frequency as well as the impacts of environmental temperature on the quantum speed limit in both cases, i.e., spinboson system with and without tunneling term. [Preview Abstract] 
Monday, March 13, 2017 10:48AM  11:00AM 
A46.00013: Probability Distributions for Random Quantum Operations Kevin Schultz Motivated by uncertainty quantification and inference of quantum information systems, in this work we draw connections between the notions of random quantum states and operations in quantum information with probability distributions commonly encountered in the field of orientation statistics. This approach identifies natural sample spaces and probability distributions upon these spaces that can be used in the analysis, simulation, and inference of quantum information systems. The theory of exponential families on Stiefel manifolds provides the appropriate generalization to the classical case. Furthermore, this viewpoint motivates a number of additional questions into the convex geometry of quantum operations relative to both the differential geometry of Stiefel manifolds as well as the information geometry of exponential families defined upon them. In particular, we draw on results from convex geometry to characterize which quantum operations can be represented as the average of a random quantum operation. [Preview Abstract] 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2020 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700