Introduction to entanglement theory & Detection of multipartite entanglement close to symmetric Dicke states
|
|
- Austin Lamb
- 5 years ago
- Views:
Transcription
1 Introduction to entanglement theory & Detection of multipartite entanglement close to symmetric Dicke states G. Tóth 1,2,3 Collaboration: Entanglement th.: G. Vitagliano 1, I. Apellaniz 1, I.L. Egusquiza 1, Cold gas exp.: B. Lücke 4, J. Peise 4, J. Arlt 4, L. Santos 4, C. Klempt 4 1 Theoretical Physics, University of the Basque Country UPV/EHU, Bilbao, Spain 2 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain 3 Wigner Research Centre for Physics, Budapest, Hungary 4 Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany BCAM, Bilbao, 27 January / 53
2
3 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 3 / 53
4 Why multipartite entanglement is important? Full tomography is not possible, we still have to say something meaningful. Claiming entanglement is not sufficient for many particles. Many experiments are aiming to create entangled states with many atoms. Only collective quantities can be measured.
5 Notation Qubit: Ψ = α 0 + β 1, Density matrix: ϱ = k p k Ψ k Ψ k, Expectation value: A = Tr(ϱA). Variance: ( A) 2 = Tr(ϱA 2 ) Tr(ϱA) 2.
6 Defintion of Entanglement A state is (fully) separable if it can be written as p k ϱ (k) ϱ (k)... ϱ (k) 1 2 N. k If a state is not separable then it is entangled. R.F. Werner, Phys. Rev. A 1989
7 Questions for multipartite entanglement For many particles, it is not sufficient to say entangled / not entangled. We have to have more than these two levels.
8 k-producibility/k-entanglement A pure state is k-producible if it can be written as Φ = Φ 1 Φ 2 Φ 3 Φ 4... where Φ l are states of at most k qubits. A mixed state is k-producible, if it is a mixture of k-producible pure states. [ e.g., O. Gühne and GT, New J. Phys ] If a state is not k-producible, then it is at least (k + 1)-particle entangled.
9 Genuine multipartite entanglement N-particle entanglement genuine multipartite entanglement.
10 Usefulness of entanglement Entangled states are useful for quantum cryptography, for quantum teleportation. Entangled states outperform separable ones in very general tasks in quamtum metrlogy. Note: Entanglement cannot be obtained from separable states with local operations and classical communications (LOCC). It is a resource.
11 Entanglement detection It is a very hard task to decide whether a quantum state is separable or not. Solved for small systems: 2 2, 2 3. (Peres-Horodecki condition, 1997.) In general, necessary conditions for separability exist. If they are violated, then we know that the state is entangled
12 Examples Examples Two entangled states of four qubits: GHZ 4 = 1 ( ), 2 Ψ B = 1 2 ( ) = ( ). The first state is genuine multipartite entangled, the second state is biseparable.
13 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 13 / 53
14 Theory of quantum entanglement Separable states form a convex set. ρ 1 ρ 2 ρ' Entangled states Separable states
15 Theory of quantum entanglement II A more accurate picture: Boundary: Density matrices with less than full rank All quantum states (convex set) Not only curved boundaries
16 Theory of quantum entanglement III Together with the set of separable states: Pure product states are at the boundary of both sets Separable states All quantum states
17 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 17 / 53
18 Witnesses based on correlations Definition An entanglement witness W is an operator that is positive on all separable (biseparable) states. Thus, Tr(Wϱ) < 0 signals entanglement (genuine multipartite entanglement). [ Horodecki 1996; Terhal 2000; Lewenstein, Kraus, Cirac, Horodecki 2002 ] There are two main goals when searching for entanglement witnesses: Large robustness to noise Optimization Few measurements
19 Convex sets for the entanglement witnesses Entanglement witnesses in the convex set picture Quantum states detected by the witness Entangled states Separable states
20 Witnesses based on correlations Example Witness with Heisenberg interaction W xyz = σ (1) x σ (2) x + σ (1) y σ (2) y + σ (1) z σ (2) z. Proof. For product states of the form Ψ = Ψ 1 Ψ 2, we have σ x σ x + σ y σ y + σ z σ z = l=x,y,z σ l Ψ1 σ l Ψ2 1. Here, we used the Cauchy-Schwarz inequality. Due to convexity, the inequality is also true for separable states. The minimum for quantum states is 3. Such a maximum is obtained for the state 1 2 ( ).
21 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 21 / 53
22 Variance-based criteria For a bipartite system, for both parties ( A k ) 2 + ( B k ) 2 L k. For product states of the form Ψ = Ψ 1 Ψ 2, we have ( (A 1 + A 2 )) 2 = (A 1 + A 2 ) 2 A 1 + A 2 2 = ( A 1 ) 2 Ψ 1 + ( A 2 ) 2 Ψ 2 since for product states Hence, A 1 A 2 A 1 A 2 = 0. ( (A 1 + A 2 )) 2 + ( (B 1 + B 2 )) 2 L 1 + L 2. This is also true for separable states due to the convexity of separable states. [ See Gühne, Phys. Rev. Lett. (2004) for an exhaustive study.]
23 Variance-based criteria II Example: we have Hence, ( x) 2 ( p) ( x) 2 + ( p) 2 1. Then, for two-mode separable states ( (x 1 + x 2 )) 2 + ( (p 1 p 2 )) 2 2. Any state violating this is entangled. [ Generalization: L.M. Duan, G. Giedke, J.I. Cirac, P. Zoller, Phys. Rev. Lett (2000); R. Simon, Phys. Rev. Lett (2000).]
24 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 24 / 53
25 Experiment with photons A photon can have a horizontal (H) and a vertical (V) polarization. H/V can take the role of 0 and 1. Problem: photons do not interact with each other.
26 Photons II MPQ, Munich. Experiments with 6 photons. [ W. Wieczorek, R. Krischek, N. Kiesel, P. Michelberger, G. Tóth, and H. Weinfurter, Phys. Rev. Lett ] D (3) 6 = 1 20 ( ).
27 Photons III
28 Photons IV 6-qubit Quantum state tomography [ C. Schwemmer, G. Tóth, A. Niggebaum, T. Moroder, D. Gross, O. Gühne, and H. Weinfurter, Phys. Rev. Lett 113, (2014). ]
29 Photons VI Entanglement witness for Detecting genuine multipartite entanglement close to Dicke states W D := D(3) 6 D(3) 6, where D (3) 6 = 1 20 ( ). If we have W D < 0 then the state is genuine multipartite entangled. [G. Tóth, JOSAB 2007.]
30 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 30 / 53
31 Many-particle systems for j=1/2 For spin- 1 2 particles, we can measure the collective angular momentum operators: where l = x, y, z and σ (k) l J l := 1 2 N k=1 σ (k) l, a Pauli spin matrices. We can also measure the variances ( J l ) 2 := J 2 l J l 2.
32 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 32 / 53
33 The standard spin-squeezing criterion The spin squeezing parameter is defined as ξs 2 ( J z ) 2 = N J x 2 + J y 2. [A. Sørensen, L.M. Duan, J.I. Cirac, P. Zoller, Nature 409, 63 (2001).] If ξ 2 s < 1 then the state is entangled. States detected are like this: Variance of J z is small J x is large x y z
34 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 34 / 53
35 Generalized spin squeezing criteria for j = 1 2 Let us assume that for a system we know only J := ( Jx, J y, J z ), K := ( J 2 x, J 2 y, J 2 z ). Then any state violating the following inequalities is entangled: J 2 x + J 2 y + J 2 z N(N+2) 4, ( J x ) 2 + ( J y ) 2 + ( J z ) 2 N 2, J 2 k + J2 l (N 1)( J m ) 2 + N 2, (N 1) [ ( J k ) 2 + ( J l ) 2] J 2 m + N(N 2) 4, where k, l, m take all the possible permutations of x, y, z. [GT, C. Knapp, O. Gühne, and H.J. Briegel, PRL 99, (2007)]
36 Generalized spin squeezing criteria for j = 1 2 II Separable states are in the polytope We set J l = 0 for l = x, y, z.
37 Spin squeezing criteria Two-particle correlations All quantities needed can be obtained with two-particle correlations J l = N j l 1 ϱp2 ; J 2 l = N 4 + N(N 1) j l j l ϱp2. Here, the average 2-particle density matrix is defined as ϱ 2p = 1 ϱ mn. N(N 1) n m Still, we can detect states with a separable ϱ p2. Still, as we will see, we can even detect multipartite entanglement!
38 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 38 / 53
39 Dicke states Symmetric Dicke states with J z = 0 (simply Dicke states in the following) are defined as D N = ( N N 2 ) 1 2 k P k ( 0 N 2 1 N 2 ). E.g., for four qubits they look like D 4 = 1 6 ( ). [photons: Kiesel et al., Phys. Rev. Lett. 2007; Prevedel et al., Phys. Rev. Lett 2007; Wieczorek et al., Phys. Rev. Lett. 2009] [cold atoms: Lücke et al., Science 2011; Hamley et al., Science 2011]
40 Dicke states are useful because they possess strong multipartite entanglement, like GHZ states. [GT, JOSAB 2007.]... are optimal for quantum metrology, similarly to GHZ states. [Hyllus et al., PRA 2012;Lücke et al., Science 2011.] [GT, PRA 2012; GT and Apellaniz, J. Phys. A, special issue for 50 year of Bell s theorem, 2014.]... are macroscopically entangled, like GHZ states. [Fröwis, Dür, PRL 2011]
41 Spin Squeezing Inequality for Dicke states Let us rewrite the third inequality J 2 k + J2 l N 2 (N 1)( J m) 2. It detects states close to Dicke states since Jx 2 + Jy 2 = N ( ) N = max., J 2 z = 0.
42 Spin Squeezing Inequality for Dicke states II Based on the above inequality, we define a new spin squeezing parameter ξos 2 = RHS LHS = (N 1) ( J z ) 2 Jx 2 + J2 y N. 2 [Vitagliano, Apellaniz, Egusquiza, GT, PRA (2014)] For our Dicke state, the numerator is minimal, the denominator is maximal, ξ 2 os = 0. The original spin squeezing parameter would not detect the Dicke states, since ξs 2 ( J z ) 2 = N J x 2 + J y 2 = N ( J z) 2 =. 0
43 Fully polarized states Relation between the second moments and the expectation value J 2 x = J x 2 + ( J x ) 2 J x 2. For states polarized in the x-direction and spin squeezed along the z-direction, for N 1, we have J 2 x J x 2 N. Hence, for fully polarized states ξos 2 ( J z ) 2 = (N 1) Jx 2 + J2 y N 2 ξs 2 ( J z ) 2 = N J x 2 + J y 2.
44 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 44 / 53
45 Multipartite entanglement in spin squeezing We consider pure k-producible states of the form Ψ = M n=1 ψ(n), where ψ (n) is the state of at most k qubits. The spin-squeezing criterion for k-producible states is J x 2 + J y 2 ( J z ) 2 J max F k 2 J max, where J max = N 2 and we use the definition F j (X) := 1 j min ( j z ) 2. jx j =X [Sørensen and Mølmer, Phys. Rev. Lett. 86, 4431 (2001); experimental test: C. Gross et al., Nature 464, 1165 (2010).]
46 Multipartite entanglement around Dicke states Measure the same quantities as before ( J z ) 2 and J 2 x + J 2 y. In contrast, for the original spin-squeezing criterion we measured ( J z ) 2 and J x 2 + J y 2. Pioneering work: linear condition of Luming Duan, Phys. Rev. Lett. (2011). See also Zhang, Duan, arxiv (2014).
47 Due to convexity properties of the expression, this is also valid to mixed separable states. Multipartite entanglement - Our condition Sørensen-Mølmer condition for k-producible states Combine it with ( J z ) 2 J max F k 2 J x 2 + J y 2 J max J 2 x + J 2 y J max ( k 2 + 1) + J x 2 + J y 2, which is true for pure k-producible states. (Remember, J max = N 2.) Condition for entanglement detection around Dicke states J ( J z ) 2 x 2 + J2 y J max( k 2 + 1) J max F k 2 J max..
48 Concrete example N = 8000 particles, and J eff = Jx 2 + J2 y. Red curve: boundary for 28-particle entanglement. Blue dashed line: linear condition given in [L.-M. Duan, Phys. Rev. Lett. 107, (2011).] Red dashed line: tangent of our curve.
49 Outline 1 Motivation Why multipartite entanglement is important? 2 Quantum Entanglement Geometry of quantum states Linear entanglement witnesses Non-linear entanglement witnesses Experiments 3 Spin squeezing and entanglement Collective measurements The original spin-squeezing criterion Generalized criteria for j = Spin squeezing for Dicke states Entanglement detection close to Dicke states Detection of multipartite entanglement close to Dicke states Our conditions are stronger than the original conditions 49 / 53
50 Our condition is stronger Consider spin squeezed states as ground states of H(Λ) = J 2 z ΛJ x. For Λ =, the ground state is fully polarized. For Λ = 0, it is the symmetric Dicke state. Our condition vs. original condition for N=4000 and p=0.05 [ Lücke et al., Phys. Rev. Lett. 112, (2014). ]
51 Experimental results Bose-Einstein condensate, 8000 particles. 28-particle entanglement is detected. (a) (c) separable (b) Δ J z J z ( Jz) 2 J x J y J eff < J ^2 / J 2 eff max > [ Lücke et al., Phys. Rev. Lett. 112, (2014). ]
52 Project participants G. Vitagliano C. Klempt, B. Lücke, J. Mahnke W. Ertmer, I. Geisel, J. Peise, S. Coleman I. Apellaniz L. Santos Hannover I.L. Egusquiza Bilbao
53 Summary Detection of multipartite entanglement close to Dicke states, by measuring collective quantities only. The condition detects all entangled states that can be detected based on the measured quantities (i.e., it is optimal). Vitagliano, Apellaniz, Egusquiza, GT, PRA (2014). Lücke, Peise, Vitagliano, Arlt, Santos, GT, Klempt, PRL 112, (2014) (synopsis at physics.aps.org, Revista Española de Física). THANK YOU FOR YOUR ATTENTION! FOR TRANSPARENCIES, PLEASE SEE
Entanglement witnesses
1 / 45 Entanglement witnesses Géza Tóth 1 Theoretical Physics, University of the Basque Country UPV/EHU, Bilbao, Spain 2 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain 3 Wigner Research Centre
More informationEntanglement detection close to multi-qubit Dicke states in photonic experiments (review)
Entanglement detection close to multi-qubit Dicke states in photonic experiments (review) G. Tóth 1,2,3 1 Theoretical Physics, University of the Basque Country UPV/EHU, Bilbao, Spain 2, Bilbao, Spain 3
More informationQuantum entanglement and its detection with few measurements
Quantum entanglement and its detection with few measurements Géza Tóth ICFO, Barcelona Universidad Complutense, 21 November 2007 1 / 32 Outline 1 Introduction 2 Bipartite quantum entanglement 3 Many-body
More informationQuantum metrology from a quantum information science perspective
1 / 41 Quantum metrology from a quantum information science perspective Géza Tóth 1 Theoretical Physics, University of the Basque Country UPV/EHU, Bilbao, Spain 2 IKERBASQUE, Basque Foundation for Science,
More informationPermutationally invariant quantum tomography
/ 4 Permutationally invariant quantum tomography G. Tóth,2,3, W. Wieczorek 4,5, D. Gross 6, R. Krischek 4,5, C. Schwemmer 4,5, and H. Weinfurter 4,5 Theoretical Physics, The University of the Basque Country,
More informationQuantum Fisher information and entanglement
1 / 70 Quantum Fisher information and entanglement G. Tóth 1,2,3 1 Theoretical Physics, University of the Basque Country (UPV/EHU), Bilbao, Spain 2 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
More informationarxiv: v4 [quant-ph] 21 Oct 2014
REVIEW ARTICLE Quantum metrology from a quantum information science perspective arxiv:1405.4878v4 [quant-ph] 21 Oct 2014 Géza Tóth 1,2,3, Iagoba Apellaniz 1 1 Department of Theoretical Physics, University
More informationarxiv: v2 [quant-ph] 8 Jul 2014
TOPICAL REVIEW Quantum metrology from a quantum information science perspective arxiv:1405.4878v2 [quant-ph] 8 Jul 2014 Géza Tóth 1,2,3, Iagoba Apellaniz 1 1 Department of Theoretical Physics, University
More informationExtremal properties of the variance and the quantum Fisher information; Phys. Rev. A 87, (2013).
1 / 24 Extremal properties of the variance and the quantum Fisher information; Phys. Rev. A 87, 032324 (2013). G. Tóth 1,2,3 and D. Petz 4,5 1 Theoretical Physics, University of the Basque Country UPV/EHU,
More informationarxiv:quant-ph/ v1 28 Jun 2006
Experimental Observation of Four-Photon Entangled Dicke State with High Fidelity N. Kiesel, 1,2 C. Schmid, 1,2 G. Tóth, 1,3 E. Solano, 1, and H. Weinfurter 1,2 1 Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse
More informationWitnessing Genuine Many-qubit Entanglement with only Two Local Measurement Settings
Witnessing Genuine Many-qubit Entanglement with only Two Local Measurement Settings Géza Tóth (MPQ) Collaborator: Otfried Gühne (Innsbruck) uant-ph/0405165 uant-ph/0310039 Innbruck, 23 June 2004 Outline
More informationGenuine three-partite entangled states with a hidden variable model
Genuine three-partite entangled states with a hidden variable model Géza Tóth 1,2 and Antonio Acín 3 1 Max-Planck Institute for Quantum Optics, Garching, Germany 2 Research Institute for Solid State Physics
More informationGeneralized Bell Inequality and Entanglement Witness
Nonlocal Seminar 2005 Bratislava, April 29th 2005 Reinhold A. Bertlmann Generalized Bell Inequality and Entanglement Witness Institute for Theoretical Physics University of Vienna Motivation Composite
More informationDetecting genuine multipartite entanglement in higher dimensional systems
University of Vienna March 16, 2011 (University of Vienna) March 16, 2011 1 / 19 1 2 3 4 5 6 7 8 (University of Vienna) March 16, 2011 2 / 19 To start with some easy basics (University of Vienna) March
More information0.5 atoms improve the clock signal of 10,000 atoms
0.5 atoms improve the clock signal of 10,000 atoms I. Kruse 1, J. Peise 1, K. Lange 1, B. Lücke 1, L. Pezzè 2, W. Ertmer 1, L. Santos 3, A. Smerzi 2, C. Klempt 1 1 Institut für Quantenoptik, Leibniz Universität
More informationEntanglement of indistinguishable particles
Entanglement of indistinguishable particles Fabio Benatti Dipartimento di Fisica, Università di Trieste QISM Innsbruck -5 September 01 Outline 1 Introduction Entanglement: distinguishable vs identical
More informationEmergence of the classical world from quantum physics: Schrödinger cats, entanglement, and decoherence
Emergence of the classical world from quantum physics: Schrödinger cats, entanglement, and decoherence Luiz Davidovich Instituto de Física Universidade Federal do Rio de Janeiro Outline of the talk! Decoherence
More informationDistinguishing different classes of entanglement for three qubit pure states
Distinguishing different classes of entanglement for three qubit pure states Chandan Datta Institute of Physics, Bhubaneswar chandan@iopb.res.in YouQu-2017, HRI Chandan Datta (IOP) Tripartite Entanglement
More informationarxiv: v3 [quant-ph] 27 Feb 2009
arxiv:0811.803v3 [quant-ph] 7 Feb 009 Entanglement detection Otfried Gühne Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 1A, A-600 Innsbruck,
More informationMultipartite Einstein Podolsky Rosen steering and genuine tripartite entanglement with optical networks
Multipartite Einstein Podolsky Rosen steering and genuine tripartite entanglement with optical networks Seiji Armstrong 1, Meng Wang 2, Run Yan Teh 3, Qihuang Gong 2, Qiongyi He 2,3,, Jiri Janousek 1,
More informationQuantum States: Analysis and Realizations
Harald Weinfurter experimental quantum physics QUASAR Quantum States: Analysis and Realizations Start date: January 202 Duration: 24 months CHISTERA seminar, Istanbul, 4 March 204 Goals efficient quantum
More informationEntanglement: concept, measures and open problems
Entanglement: concept, measures and open problems Division of Mathematical Physics Lund University June 2013 Project in Quantum information. Supervisor: Peter Samuelsson Outline 1 Motivation for study
More informationMax-Planck-Institut für Mathematik in den Naturwissenschaften Leipzig
Max-Planck-Institut für Mathematik in den aturwissenschaften Leipzig Bell inequality for multipartite qubit quantum system and the maximal violation by Ming Li and Shao-Ming Fei Preprint no.: 27 2013 Bell
More informationDetection of photonic Bell states
LECTURE 3 Detection of photonic Bell states d a c Beam-splitter transformation: b ˆB ˆB EXERCISE 10: Derive these three relations V a H a ˆB Detection: or V b H b or Two photons detected in H a, H b, V
More informationOn PPT States in C K C M C N Composite Quantum Systems
Commun. Theor. Phys. (Beijing, China) 42 (2004) pp. 25 222 c International Academic Publishers Vol. 42, No. 2, August 5, 2004 On PPT States in C K C M C N Composite Quantum Systems WANG Xiao-Hong, FEI
More informationPermutations and quantum entanglement
Journal of Physics: Conference Series Permutations and quantum entanglement To cite this article: D Chruciski and A Kossakowski 2008 J. Phys.: Conf. Ser. 104 012002 View the article online for updates
More informationMax-Planck-Institut für Mathematik in den Naturwissenschaften Leipzig
Max-Planck-Institut für Mathematik in den aturwissenschaften Leipzig Genuine multipartite entanglement detection and lower bound of multipartite concurrence by Ming Li, Shao-Ming Fei, Xianqing Li-Jost,
More informationQuantum Correlations and Bell Inequality Violation under Decoherence
Quantum Correlations and Bell Inequality Violation under Decoherence Volkan Erol Computer Engineering Department, Okan University, Istanbul, 34959, Turkey E-mail: volkan.erol@gmail.com Abstract Quantum
More informationQuantum metrology with Dicke squeezed states
PAPER OPEN ACCESS Quantum metrology with Dicke squeezed states To cite this article: 2014 New J. Phys. 16 103037 View the article online for updates and enhancements. Related content - Spin squeezing,
More informationQuantum Correlations as Necessary Precondition for Secure Communication
Quantum Correlations as Necessary Precondition for Secure Communication Phys. Rev. Lett. 92, 217903 (2004) quant-ph/0307151 Marcos Curty 1, Maciej Lewenstein 2, Norbert Lütkenhaus 1 1 Institut für Theoretische
More informationTwo-setting Bell inequalities for graph states
PHYSICAL REVIEW A 73, 022303 2006 Two-setting Bell inequalities for graph states Géza Tóth, 1,2, * Otfried Gühne, 3, and Hans J. Briegel 3,4, 1 Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße
More informationQuantum Entanglement- Fundamental Aspects
Quantum Entanglement- Fundamental Aspects Debasis Sarkar Department of Applied Mathematics, University of Calcutta, 92, A.P.C. Road, Kolkata- 700009, India Abstract Entanglement is one of the most useful
More informationEinstein-Podolsky-Rosen-like correlation on a coherent-state basis and Continuous-Variable entanglement
12/02/13 Einstein-Podolsky-Rosen-like correlation on a coherent-state basis and Continuous-Variable entanglement Ryo Namiki Quantum optics group, Kyoto University 京大理 並木亮 求職中 arxiv:1109.0349 Quantum Entanglement
More informationTheory of Quantum Entanglement
Theory of Quantum Entanglement Shao-Ming Fei Capital Normal University, Beijing Universität Bonn, Bonn Richard Feynman 1980 Certain quantum mechanical effects cannot be simulated efficiently on a classical
More informationAverage Fidelity of Teleportation in Quantum Noise Channel
Commun. Theor. Phys. (Beijing, China) 45 (006) pp. 80 806 c International Academic Publishers Vol. 45, No. 5, May 15, 006 Average Fidelity of Teleportation in Quantum Noise Channel HAO Xiang, ZHANG Rong,
More informationarxiv: v2 [quant-ph] 21 Oct 2013
Genuine hidden quantum nonlocality Flavien Hirsch, 1 Marco Túlio Quintino, 1 Joseph Bowles, 1 and Nicolas Brunner 1, 1 Département de Physique Théorique, Université de Genève, 111 Genève, Switzerland H.H.
More informationHong-Ou-Mandel effect with matter waves
Hong-Ou-Mandel effect with matter waves R. Lopes, A. Imanaliev, A. Aspect, M. Cheneau, DB, C. I. Westbrook Laboratoire Charles Fabry, Institut d Optique, CNRS, Univ Paris-Sud Progresses in quantum information
More informationCharacterization of Bipartite Entanglement
Characterization of Bipartite Entanglement Werner Vogel and Jan Sperling University of Rostock Germany Paraty, September 2009 Paraty, September 2009 UNIVERSITÄT ROSTOCK INSTITUT FÜR PHYSIK 1 Table of Contents
More informationTHE INTERFEROMETRIC POWER OF QUANTUM STATES GERARDO ADESSO
THE INTERFEROMETRIC POWER OF QUANTUM STATES GERARDO ADESSO IDENTIFYING AND EXPLORING THE QUANTUM-CLASSICAL BORDER Quantum Classical FOCUSING ON CORRELATIONS AMONG COMPOSITE SYSTEMS OUTLINE Quantum correlations
More informationA new experimental apparatus for quantum atom optics
A new experimental apparatus for quantum atom optics Andreas Hüper, Jiao Geng, Ilka Kruse, Jan Mahnke, Wolfgang Ertmer and Carsten Klempt Institut für Quantenoptik, Leibniz Universität Hannover Outline
More informationarxiv:quant-ph/ v2 12 Apr 2006
Two-setting Bell Inequalities for Graph States Géza Tóth, 1,2, Otfried Gühne, 3, and Hans J. Briegel 3,4, 1 Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, D-85748 Garching, Germany, 2
More informationQuantum entanglement and symmetry
Journal of Physics: Conference Series Quantum entanglement and symmetry To cite this article: D Chrucisi and A Kossaowsi 2007 J. Phys.: Conf. Ser. 87 012008 View the article online for updates and enhancements.
More informationGeneration and classification of robust remote symmetric Dicke states
Vol 17 No 10, October 2008 c 2008 Chin. Phys. Soc. 1674-1056/2008/17(10)/3739-05 Chinese Physics B and IOP Publishing Ltd Generation and classification of robust remote symmetric Dicke states Zhu Yan-Wu(
More informationNon-locality of Symmetric States
Non-locality of Symmetric States Damian Markham Joint work Click with: to edit Master subtitle style Zizhu Wang CNRS, LTCI ENST (Telecom ParisTech), Paris quant- Motivation Non-locality as an interpretation/witness
More informationMultipartite entangled coherent states
PHYSICAL REVIEW A, VOLUME 65, 012303 Multipartite entangled coherent states Xiaoguang Wang 1,2 and Barry C. Sanders 3 1 Institute of Physics and Astronomy, University of Aarhus, Aarhus, DK-8000, Denmark
More informationUncertainty Relations, Unbiased bases and Quantification of Quantum Entanglement
Uncertainty Relations, Unbiased bases and Quantification of Quantum Entanglement Karol Życzkowski in collaboration with Lukasz Rudnicki (Warsaw) Pawe l Horodecki (Gdańsk) Jagiellonian University, Cracow,
More informationScheme for implementing perfect quantum teleportation with four-qubit entangled states in cavity quantum electrodynamics
Scheme for implementing perfect quantum teleportation with four-qubit entangled states in cavity quantum electrodynamics Tang Jing-Wu( ), Zhao Guan-Xiang( ), and He Xiong-Hui( ) School of Physics, Hunan
More informationApplication of Structural Physical Approximation to Partial Transpose in Teleportation. Satyabrata Adhikari Delhi Technological University (DTU)
Application of Structural Physical Approximation to Partial Transpose in Teleportation Satyabrata Adhikari Delhi Technological University (DTU) Singlet fraction and its usefulness in Teleportation Singlet
More informationNo Fine theorem for macroscopic realism
No Fine theorem for macroscopic realism Johannes Kofler Max Planck Institute of Quantum Optics (MPQ) Garching/Munich, Germany 2nd International Conference on Quantum Foundations Patna, India 17 Oct. 2016
More informationQuantification of Gaussian quantum steering. Gerardo Adesso
Quantification of Gaussian quantum steering Gerardo Adesso Outline Quantum steering Continuous variable systems Gaussian entanglement Gaussian steering Applications Steering timeline EPR paradox (1935)
More informationarxiv: v2 [quant-ph] 16 Nov 2018
aaacxicdvhlsgmxfe3hv62vvswncwelkrmikdlgi7cqc1yfwyro+mthmasibkjlgg+wk3u/s2/wn8wfsxs1qsjh3nuosckjhcuhb8fry5+yxfpejyawv1bx2jxnm8tto1hftcs23ui7aohciwcjnxieojjf/xphvrdcxortlqhqykdgj6u6ako5kjmwo5gtsc0fi/qtgbvtaxmolcnxuap7gqihlspyhdblqgbicil5q1atid3qkfhfqqo+1ki6e5f+cyrt/txh1f/oj9+skd2npbhlnngojzmpd8k9tyjdw0kykioniem9jfmxflvtjmjlaseio9n9llpk/ahkfldycthdga3aj3t58/gwfolthsqx2olgidl87cdyigsjusbud182x0/7nbjs9utoacgfz/g1uj2phuaubx9u6fyy7kljdts8owchowj1dsarmc6qvbi39l78ta8bw9nvoovjv1tsanx9rbsmy8zw==
More informationCurriculum vitæ for Géza Tóth August 17, 2015
Curriculum vitæ for Géza Tóth August 17, 2015 Date of birth August, 1971 Citizenship Hungarian Marital status Family with 1 child (Dec 2005) Contact Department of Theoretical Physics, Phone: +34-94-601-7926
More informationarxiv: v2 [quant-ph] 12 Oct 2017
Sequentially generated entanglement, macroscopicity and squeezing in a spin chain Tahereh Abad, 1, Klaus Mølmer, and Vahid Karimipour 1 1 Department of Physics, Sharif University of Technology, Tehran,
More informationSingle-Particle Interference Can Witness Bipartite Entanglement
Single-Particle Interference Can Witness ipartite Entanglement Torsten Scholak 1 3 Florian Mintert 2 3 Cord. Müller 1 1 2 3 March 13, 2008 Introduction Proposal Quantum Optics Scenario Motivation Definitions
More informationNo Fine Theorem for Macrorealism
No Fine Theorem for Macrorealism Johannes Kofler Max Planck Institute of Quantum Optics (MPQ) Garching/Munich, Germany Quantum and Beyond Linnaeus University, Växjö, Sweden 14 June 2016 Acknowledgments
More informationShared Purity of Multipartite Quantum States
Shared Purity of Multipartite Quantum States Anindya Biswas Harish-Chandra Research Institute December 3, 2013 Anindya Biswas (HRI) Shared Purity December 3, 2013 1 / 38 Outline of the talk 1 Motivation
More informationarxiv: v3 [quant-ph] 11 Dec 2018
The stabilizer for n-qubit symmetric states Xian Shi Institute of Mathematics, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China University of Chinese Academy
More informationDYNAMICS OF ENTANGLEMENT OF THREE-MODE GAUSSIAN STATES IN THE THREE-RESERVOIR MODEL
DYNAMICS OF ENTANGLEMENT OF THREE-MODE GAUSSIAN STATES IN THE THREE-RESERVOIR MODEL HODA ALIJANZADEH BOURA 1,,a, AURELIAN ISAR,b, YAHYA AKBARI KOURBOLAGH 1,c 1 Department of Physics, Azarbaijan Shahid
More informationarxiv:quant-ph/ v3 17 Jul 2005
Quantitative measures of entanglement in pair coherent states arxiv:quant-ph/0501012v3 17 Jul 2005 G. S. Agarwal 1 and Asoka Biswas 2 1 Department of Physics, Oklahoma state University, Stillwater, OK
More informationBell tests in physical systems
Bell tests in physical systems Seung-Woo Lee St. Hugh s College, Oxford A thesis submitted to the Mathematical and Physical Sciences Division for the degree of Doctor of Philosophy in the University of
More informationBipartite Continuous-Variable Entanglement. Werner Vogel Universität Rostock, Germany
Bipartite Continuous-Variable Entanglement Werner Vogel Universität Rostock, Germany Contents Introduction NPT criterion for CV entanglement Negativity of partial transposition Criteria based on moments
More informationEntanglement Polytopes
Entanglement Polytopes Detecting Genuine Multi-Particle Entanglement by Single-Particle Measurements Michael Walter joint work with Matthias Christandl, Brent Doran (ETH Zürich), and David Gross (Univ.
More informationarxiv: v1 [quant-ph] 15 Feb 2014
Open-System Dynamics of Entanglement Leandro Aolita, 1 Fernando de Melo, 2 and Luiz Davidovich 3 1 Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany 2 Centro Brasileiro
More informationThe feasible generation of entangled spin-1 state using linear optical element
The feasible generation of entangled spin-1 state using linear optical element XuBo Zou, K. Pahlke and W. Mathis Institute TET, University of Hannover, Appelstr. 9A, 30167 Hannover, Germany Abstract We
More informationEvaluation Method for Inseparability of Two-Mode Squeezed. Vacuum States in a Lossy Optical Medium
ISSN 2186-6570 Evaluation Method for Inseparability of Two-Mode Squeezed Vacuum States in a Lossy Optical Medium Genta Masada Quantum ICT Research Institute, Tamagawa University 6-1-1 Tamagawa-gakuen,
More informationQuantum mechanics and reality
Quantum mechanics and reality Margaret Reid Centre for Atom Optics and Ultrafast Spectroscopy Swinburne University of Technology Melbourne, Australia Thank you! Outline Non-locality, reality and quantum
More informationarxiv: v1 [quant-ph] 15 Jul 2014
Experimental entanglement redistribution under decoherence channels G. H. Aguilar, A. Valdés-Hernández, L. Davidovich, S. P. Walborn, and P. H. Souto Ribeiro Instituto de Física, Universidade Federal do
More informationarxiv:quant-ph/ Mar 2006
Scalable multi-particle entanglement of trapped ions H. Häffner 1,2, W. Hänsel 1, C. F. Roos 1,2, J. Benhelm 1,2, D. Chek al kar 1, M. Chwalla 1, T. Körber 1,2, U. D. Rapol 1,2, M. Riebe 1, P. O. Schmidt
More informationTensors and complexity in quantum information science
Tensors in CS and geometry workshop, Nov. 11 (2014) Tensors and complexity in quantum information science Akimasa Miyake 1 CQuIC, University of New Mexico Outline Subject: math of tensors physics of
More informationarxiv: v4 [quant-ph] 28 Feb 2018
Tripartite entanglement detection through tripartite quantum steering in one-sided and two-sided device-independent scenarios arxiv:70086v [quant-ph] 8 Feb 08 C Jebaratnam,, Debarshi Das,, Arup Roy, 3
More informationQuantum entanglement and macroscopic quantum superpositions
Max Planck Institute of Quantum Optics (MPQ) Garching / Munich, Germany Quantum entanglement and macroscopic quantum superpositions Johannes Kofler Quantum Information Symposium Institute of Science and
More informationEstimation of Optimal Singlet Fraction (OSF) and Entanglement Negativity (EN)
Estimation of Optimal Singlet Fraction (OSF) and Entanglement Negativity (EN) Satyabrata Adhikari Delhi Technological University satyabrata@dtu.ac.in December 4, 2018 Satyabrata Adhikari (DTU) Estimation
More informationQuantum Networks with Atomic Ensembles
Quantum Networks with Atomic Ensembles Daniel Felinto* dfelinto@df.ufpe.br C.W. Chou, H. Deng, K.S. Choi, H. de Riedmatten, J. Laurat, S. van Enk, H.J. Kimble Caltech Quantum Optics *Presently at Departamento
More informationQuantum computing and quantum communication with atoms. 1 Introduction. 2 Universal Quantum Simulator with Cold Atoms in Optical Lattices
Quantum computing and quantum communication with atoms L.-M. Duan 1,2, W. Dür 1,3, J.I. Cirac 1,3 D. Jaksch 1, G. Vidal 1,2, P. Zoller 1 1 Institute for Theoretical Physics, University of Innsbruck, A-6020
More informationGerardo Adesso. Davide Girolami. Alessio Serafini. University of Nottingham. University of Nottingham. University College London
Gerardo Adesso University of Nottingham Davide Girolami University of Nottingham Alessio Serafini University College London arxiv:1203.5116; Phys. Rev. Lett. (in press) A family of useful additive entropies
More informationarxiv: v1 [quant-ph] 8 Feb 2016
An analytical condition for the violation of Mer s inequality by any three qubit state Satyabrata Adhikari 1, and A. S. Majumdar 2, 1 Birla Institute of Technology Mesra, Ranchi-835215, India 2 S. N. Bose
More informationPerfect quantum teleportation and dense coding protocols via the 2N-qubit W state
Perfect quantum teleportation and dense coding protocols via the -qubit W state Wang Mei-Yu( ) a)b) and Yan Feng-Li( ) a)b) a) College of Physics Science and Information Engineering, Hebei ormal University,
More informationCoherence, Discord, and Entanglement: Activating one resource into another and beyond
586. WE-Heraeus-Seminar Quantum Correlations beyond Entanglement Coherence, Discord, and Entanglement: Activating one resource into another and beyond Gerardo School of Mathematical Sciences The University
More informationA Superluminal communication solution based on Four-photon entanglement
A Superluminal communication solution based on Four-photon entanglement Jia-Run Deng cmos001@163.com Abstract : Based on the improved design of Four-photon entanglement device and the definition of Encoding
More informationExploring finite-dimensional Hilbert spaces by Quantum Optics. PhD Candidate: Andrea Chiuri PhD Supervisor: Prof. Paolo Mataloni
Exploring finite-dimensional Hilbert spaces by Quantum Optics PhD Candidate: PhD Supervisor: Prof. Paolo Mataloni Outline t Introduction to Quantum Optics t Entanglement and Hyperentanglement t Some Experiments
More informationBose-Einstein condensates & tests of quantum mechanics
Bose-Einstein condensates & tests of quantum mechanics Poul Lindholm Pedersen Ultracold Quantum Gases Group PhD day, 31 10 12 Bose-Einstein condensation T high Classical particles T = 0 Pure condensate
More informationEntanglement Measures and Monotones
Entanglement Measures and Monotones PHYS 500 - Southern Illinois University March 30, 2017 PHYS 500 - Southern Illinois University Entanglement Measures and Monotones March 30, 2017 1 / 11 Quantifying
More informationarxiv:quant-ph/ v1 27 Jul 2005
Negativity and Concurrence for two qutrits arxiv:quant-ph/57263v 27 Jul 25 Suranjana Rai and Jagdish R. Luthra ( ) Raitech, Tuscaloosa, AL 3545 ( ) Departamento de Física, Universidad de los Andes, A.A.
More informationMACROSCOPIC SUPERPOSITIONS AND QUANTUM INFORMATION PROCESSING
The 3rd KIAS Workshop on Quantum Information and Thermodynamics MACROSCOPIC SUPERPOSITIONS AND QUANTUM INFORMATION PROCESSING Hyunseok Jeong Department of Physics and Astronomy Seoul National University
More informationExperimental state and process reconstruction. Philipp Schindler + Thomas Monz Institute of Experimental Physics University of Innsbruck, Austria
Experimental state and process reconstruction Philipp Schindler + Thomas Monz Institute of Experimental Physics University of Innsbruck, Austria What do we want to do? Debug and characterize a quantum
More informationTowards quantum metrology with N00N states enabled by ensemble-cavity interaction. Massachusetts Institute of Technology
Towards quantum metrology with N00N states enabled by ensemble-cavity interaction Hao Zhang Monika Schleier-Smith Robert McConnell Jiazhong Hu Vladan Vuletic Massachusetts Institute of Technology MIT-Harvard
More informationGeneralized conditions for genuine multipartite continuous-variable entanglement
Generalized conditions for genuine multipartite continuous-variable entanglement E. Shchukin and P. van Loock Johannes-Gutenberg University of Mainz, Institute of Physics, Staudingerweg 7, 55128 Mainz
More informationMinimum Uncertainty for Entangled States
Minimum Uncertainty for Entangled States Tabish Qureshi Centre for Theoretical Physics Jamia Millia Islamia New Delhi - 110025. www.ctp-jamia.res.in Collaborators: N.D. Hari Dass, Aditi Sheel Tabish Qureshi
More informationQuantum Communication with Atomic Ensembles
Quantum Communication with Atomic Ensembles Julien Laurat jlaurat@caltech.edu C.W. Chou, H. Deng, K.S. Choi, H. de Riedmatten, D. Felinto, H.J. Kimble Caltech Quantum Optics FRISNO 2007, February 12, 2007
More informationEinstein-Podolsky-Rosen correlations and Bell correlations in the simplest scenario
Einstein-Podolsky-Rosen correlations and Bell correlations in the simplest scenario Huangjun Zhu (Joint work with Quan Quan, Heng Fan, and Wen-Li Yang) Institute for Theoretical Physics, University of
More informationQuantum Entanglement: Detection, Classification, and Quantification
Quantum Entanglement: Detection, Classification, and Quantification Diplomarbeit zur Erlangung des akademischen Grades,,Magister der Naturwissenschaften an der Universität Wien eingereicht von Philipp
More informationQUANTUM INFORMATION with light and atoms. Lecture 2. Alex Lvovsky
QUANTUM INFORMATION with light and atoms Lecture 2 Alex Lvovsky MAKING QUANTUM STATES OF LIGHT 1. Photons 2. Biphotons 3. Squeezed states 4. Beam splitter 5. Conditional measurements Beam splitter transformation
More informationCS/Ph120 Homework 4 Solutions
CS/Ph10 Homework 4 Solutions November 3, 016 Problem 1: Robustness of GHZ and W states, part Solution: Due to Bolton Bailey a For the GHZ state, we have T r N GHZ N GHZ N = 1 0 N 1 0 N 1 + 1 N 1 1 N 1
More informationarxiv: v1 [quant-ph] 4 Jul 2013
GEOMETRY FOR SEPARABLE STATES AND CONSTRUCTION OF ENTANGLED STATES WITH POSITIVE PARTIAL TRANSPOSES KIL-CHAN HA AND SEUNG-HYEOK KYE arxiv:1307.1362v1 [quant-ph] 4 Jul 2013 Abstract. We construct faces
More informationMonogamy and Polygamy of Entanglement. in Multipartite Quantum Systems
Applie Mathematics & Information Sciences 4(3) (2010), 281 288 An International Journal c 2010 Dixie W Publishing Corporation, U. S. A. Monogamy an Polygamy of Entanglement in Multipartite Quantum Systems
More informationTrivariate analysis of two qubit symmetric separable state
Pramana J. Phys. (8) 9:4 https://doi.org/.7/s4-8-598-x Indian Academy of Sciences Trivariate analysis of two qubit symmetric separable state SPSUMA and SWARNAMALA SIRSI Department of Physics, Yuvaraa s
More informationEntropic Uncertainty Relations, Unbiased bases and Quantification of Quantum Entanglement
Entropic Uncertainty Relations, Unbiased bases and Quantification of Quantum Entanglement Karol Życzkowski in collaboration with Lukasz Rudnicki (Warsaw) Pawe l Horodecki (Gdańsk) Phys. Rev. Lett. 107,
More informationarxiv: v1 [quant-ph] 27 Oct 2014
Entangled Entanglement: The Geometry of GHZ States Gabriele Uchida, 1 Reinhold A. Bertlmann, and Beatrix C. Hiesmayr, 3 1 University of Vienna, Faculty of Computer Science, Währinger Strasse 9, 1090 Vienna,
More informationExperimental violation of multipartite Bell inequalities with trapped ions
Experimental violation of multipartite Bell inequalities with trapped ions B. P. Lanyon 1,2, M. Zwerger 3, P. Jurcevic 1,2, C. Hempel 1,2, W. Dür 3, H. J. Briegel 1,3, R. Blatt 1,2, and C. F. Roos 1,2
More informationBell and Leggett-Garg inequalities in tests of local and macroscopic realism
Max Planck Institute of Quantum Optics (MPQ) Garching / Munich, Germany Bell and Leggett-Garg inequalities in tests of local and macroscopic realism Johannes Kofler University of Valencia, Spain 25 June
More information