A comparison is made of various searching procedures, based upon different entanglement measures or indicators, for highly entangled multi-qubits states.In particular, our present results are compared with those recently reported by Brown et al. [J.Phys.A: Math.Gen. 2005

We improve the test to show impossibility of a quantum theory based on real numbers by larger ratio complex-to-real bound Bell-type parameter. In contrast previous theoretical and experimental proposals requires three settings for parties <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>A</mml:mi></mml:math> xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>C</mml:mi></mml:math>, but also six middle party...

Nonlocality and quantum entanglement constitute two special features of systems paramount importance in quantum-information theory (QIT). Essentially regarded as identical or equivalent for many years, they different concepts. Describing nonlocality by means the maximal violation Bell inequalities, we study both three spins $\mathit{XY}$ model. Our results shed light on description possible information-theoretic task limitations an infinite system.

Nonlocality and quantum entanglement constitute two special aspects of the correlations existing in systems, which are paramount importance quantum-information theory. Traditionally, they have been regarded as identical (equivalent, fact, for pure qubit states, that is, {\it Gisin's Theorem}), yet different resources. Describing nonlocality by means violation several Bell inequalities, we obtain direct optimization those states qubits maximally violate a inequality, terms their degree...

It is a well-known fact that both quantum entanglement and nonlocality (implied by the violation of Bell inequalities) constitute correlations cannot be arbitrarily shared among subsystems. They are monogamous, albeit in different fashion. In present contribution we focus on monogamy relations such as Toner-Verstraete, Seevinck, derived inequality for three parties compare them with multipartite measures whole set pure states distributed according to Haar measure. this numerical endeavor,...

We study the minimum energy equilibrium configurations of a classical two-dimensional system point charges confined by triangular, square and disk region with hard-wall boundary. It is assumed that interact via repulsive Coulomb interaction potential. Monte Carlo simulations annealing algorithm suggest given are strongly influenced external (isotropic/anisotropic) geometry The numerically obtained energies extrapolated in bulk limit converge to expected continuum values (when known). found...

Langevin Dynamics numerical simulations have been used to compute the force profiles that dipolar polymer brushes exert onto a penetrating colloidal particle. It has observed are strongly influenced by externally applied fields: at large distances from grafting surface, barrier appears, and shorter region with lower repulsive forces develops. Furthermore, right combination of density, chain length strength external field, it is possible observe in this intermediate both existence net...

Many-particle systems pose commonly known computational challenges in quantum theory. The obstacles arise from the difficulty finding sets of eigenvalues and eigenvectors underlying Hamiltonian while enforcing fermion or boson statistics, not to mention prohibitive increase cost with system’s size. first obvious step this direction is elaborate theory for Fermi Bose gases without inter-particle interactions. traditional approach work ideal confined a cubic container impenetrable walls (in...

We study the matter-wave solitons in Bose-Einstein condensate (BEC) trapped on a M\"{o}bius strip (MS), based respective Gross-Pitaevskii (GP) equation with mean-field theory. In linear regime, vortex states are characterized by quantum numbers, $n$ and $m$, corresponding to transverse circumferential directions, phase structure determined winding number (WN) $m$. Odd even values of must associate, respectively, integer half-integer latter ones requiring two cycles motion around MS for...

Abstract No‐signaling is a consequence of the no‐communication theorem that states bipartite systems cannot transfer information unless communication channel exists. It also by‐product assumptions Bell about quantum nonlocality. tested in qubits from IBM Quantum devices extremely large statistics, resulting significant violations. Although time and space scales principle rule out subluminal communications, there no obvious physical mechanism leading to signaling. Such signaling not universal...

It has been recently pointed out [V. Giovannetti, S. Lloyd, and L. Maccone, Europhys. Lett. 62, 615 (2003)] that, for certain classes of states, quantum entanglement enhances the ``speed'' evolution composite systems, as measured by time a given initial state requires to evolve an orthogonal state. We provide here systematic study this effect pure states bipartite systems low dimensionality, considering both distinguishable (two-qubits) subsystems, constituted two indistinguishable particles.

Abstract We demonstrate an implementation of the precise test dimension on qubit, using public IBM quantum computer, determinant witness. The accuracy is below 10 −3 comparing to maximal possible value witness in higher dimension. involving minimal independent sets preparation and measurement operations (gates) applied both for specific configurations parametric ones. robust against nonidealities such as incoherent leakage erroneous gate execution. Two devices failed by more than 5 standard...

We revisit the relationship between quantum separability and sign of relative q-entropies composite systems. The depend on density matrix eigenvalues pi through quantity ωq = ∑ipqi. Rényi's Tsallis' measures constitute particular instances these entropies. perform a systematic numerical survey space mixed states two-qubit systems in order to determine, as function degree mixture, for different values entropic parameter q, volume state occupied by those characterized positive entropy. Similar...

We find the minimal number of settings to test quantum theory based on real numbers, assuming separability sources, modifying recent proposal [M.-O. Renou et al., Nature 600, 625 (2021)]. The needs only three for observers $A$ and $C$, but ratio complex maximum is smaller than in existing proposal. also found that two outcomes both observes are insufficient.