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Spin chains

At least one qubit is different from all others and can be addressed individually this can be simply the final spin of a spin chain. [Pg.47]

As already stated in the introduction, no long-range order can be achieved at finite temperatures for strictly ID systems. Therefore the ground state of a spin chain can be schematized as in Figure 4.8 with domains of oppositely oriented... [Pg.101]

Fig. 9 Well isolated spin chain of [0-Me2TTF(PPh2)2][W(CO)4]2 + cations in the [o-Me2TTF (PPh2)2][W(CO)4]2 [Mo6019] cation radical salt. Hydrogen atoms, phenyl rings, [Mo6Oi9]-2 anions and CO groups have been omitted for clarity... Fig. 9 Well isolated spin chain of [0-Me2TTF(PPh2)2][W(CO)4]2 + cations in the [o-Me2TTF (PPh2)2][W(CO)4]2 [Mo6019] cation radical salt. Hydrogen atoms, phenyl rings, [Mo6Oi9]-2 anions and CO groups have been omitted for clarity...
Very often, however, these dyads are not isolated in the solid state and interact with neighboring ones at least along one preferential direction. In this case, we can distinguish two important situations the alternated spin chain and the spin ladder. As shown in Scheme 5, the alternated spin chain is characterized with two different magnetic interactions, noted / and aJ with 0 < a < 1. Note that if a = 0, one recovers the singlet-triplet behavior while if a = 1, we are in the presence of a uniform spin chain. The spin ladder is also characterized by two J values, noted J// and J in the following. [Pg.173]

There is a fundamental difference between the uniform spin chain on one hand and the alternated spin chain or spin ladder on the other. Indeed, in the latter cases, the ground state is the singlet state and the susceptibility thus goes to zero at the lowest temperatures, with an activated part of the susceptibility between 0 and T (Xmax)- On the other hand, as shown by Bonner and Fisher [65], in the uniform spin... [Pg.173]

Scheme 5 Models of the spin chain (left) and the spin ladder (right). The black dots represent the spin carriers... Scheme 5 Models of the spin chain (left) and the spin ladder (right). The black dots represent the spin carriers...
We have seen above several examples where [Cp2M(dt)]+ (M = Mo, W) complexes organize in the solid state into low dimensional structures, leading to characteristic magnetic behaviors such as spin chains (eventually alternated) or spin ladders. The extensive use in later years of dithiolene ligands such as dmit or dddt was aimed at... [Pg.180]

Fannes, M., Nachtergaele, B., Werner, R.F. Finitely correlated states on quantum spin chains. Comm. Math. Phys. 1992, 144(3), 443. [Pg.161]

Demirplak and Rice developed the counter-diabatic control protocol while studying control methods that efficiently transfer population between a selected initial state and a selected target state of an isolated molecule [11-13]. The protocol has been studied for manipulation of atomic and molecular states [11, 12, 19] and spin chain systems [20, 21]. Experiments with the counter-diabatic protocol have been demonstrated for the control of BECs [22] and the electron spin of a single nitrogen-vacancy center in diamond [23]. The counter-diabatic field (CDF) protocol is identical with the transitionless driving protocol, independently proposed by Berry a few years later [24]. A discussion of the relationship between these approaches and several of the other proposed shortcuts to adiabaticity can be found in the review by Torrontegui and coworkers [10]. [Pg.53]

Optimal Control of Transfer in a Homogeneous Spin-Chain Channel... [Pg.201]

Kovacic polyphenylene is brown with about 1 spin/chain detectable by ESR. Yamamoto polymer is yellow with a shorter chain length and fewer spins. In Kovacic polymer the spins and colour may both be due to polynuclear species. Polyphenylene produced from the poly(dihydrocatechol) precursor 249) is also yellow, but has a high molecular weight, of the order of 10s. It contains about 15% o-linkages, and the aromatization procedure may leave a high level of twists in the chain originating from the flexible precursor. This material dopes only to low levels of conductivity with sodium naphthalide (6x 10 3 Scm-1) and iron chloride (1.5 x 10-2 Scm-1) but reaches a level comparable to Kovacic and Yamamoto polyphenylenes with AsFs (102 S cm-1). [Pg.41]

A spin ladder is an array of coupled spin chains. The horizontal chains are called the legs, the vertical ones, rungs. In the case of spin one-half antiferromagnet spin-ladders, these systems show a. remarkable behaviour in function of the number of leg there is a gap in the excitation spectrum of even-leg ladders and, on the contrary, no gap in the excitation spectrum of odd-leg ladders. In terms of correlation lengths, this means that there is short (long) -range spin correlation in even (odd) -legladder (see [24] for a review). [Pg.171]

The simplest spin chain consists of equivalent spin centers M with local spins S = 1/2 and uniform exchange energies, /cx ... [Pg.90]

An antiferromagnetically coupled spin dimer of two s=l/2 has a spin singlet as its lowest energy state. The first excited state is a spin triplet and the energy between these two states is denoted as the spin gap A. If such dimers are coupled in one dimension a dimerized spin chain is formed. Such spin chains exist in several spin systems, e.g. in CuGeC>3 [5], Properties of this and related compounds are further discussed in Ref. [3],... [Pg.174]

Longitudinal fluctuations of a Neel-ordered state are usually strongly damped and not included in a spin-wave approximation of its excitation spectrum. Until now similar modes have been only observed in neutron scattering on spin chain systems as broadened maxima [44 46]. The present narrow linewidth is probably related to the small scattering vector involved in light scattering experiments. [Pg.178]

High magnetic field behavior of the quantum energy gap in the Haldane spin chain systems NENP and NINO. [Pg.241]

Figure 5 Diamagnetic rings currents, Nx z), of half-filled Pariser-Parr-Pople models for regular polygons with D h symmetry. The dashed line at 2 = U/4 t0 = 1.17 corresponds to standard parameters z = 0 is the Hiickel limit of free electrons, while z 1 is the strong-correlation limit of antiferromagnetic Heisenberg spin chain with vanishing ring currents [50]. Figure 5 Diamagnetic rings currents, Nx z), of half-filled Pariser-Parr-Pople models for regular polygons with D h symmetry. The dashed line at 2 = U/4 t0 = 1.17 corresponds to standard parameters z = 0 is the Hiickel limit of free electrons, while z 1 is the strong-correlation limit of antiferromagnetic Heisenberg spin chain with vanishing ring currents [50].
For negative values of t, we obtain the uniform Heisenberg spin chain with antiferromagnetic coupling which has a nondegenerate singlet ground state. [Pg.713]

The paper is organized as follows. In See.2 we consider the frustrated spin chain at F-AF transition point and describe the exact singlet ground-state wave function as well as details of the spin correlation function calculations. We discuss the phase diagram of this model and its magnetic properties in the AF phase. In Sec.3 the special spin ladder will be considered. A two-dimensional frustrated spin model with the exact ground state is considered in Sec.4. Sec. 5 is devoted to the construction of the electronic models with the SB type of wave function. The results of this paper are summarized in Sec.6. [Pg.771]

Let us consider the s = spin chain with nearest- and next-nearest interactions given by the Hamiltonian... [Pg.771]

Figure 12 The product of susceptibility time temperature is shown as a function of temperature for four ferrimagnetic spin chains. Each chain alternates a Y = 1 /2 spin and a second, larger spin S. The dashed lines at low temperatures correspond to the xuT values for ferromagnetic spins of S-1/2 ... Figure 12 The product of susceptibility time temperature is shown as a function of temperature for four ferrimagnetic spin chains. Each chain alternates a Y = 1 /2 spin and a second, larger spin S. The dashed lines at low temperatures correspond to the xuT values for ferromagnetic spins of S-1/2 ...

See other pages where Spin chains is mentioned: [Pg.47]    [Pg.58]    [Pg.102]    [Pg.178]    [Pg.26]    [Pg.101]    [Pg.161]    [Pg.176]    [Pg.179]    [Pg.187]    [Pg.196]    [Pg.199]    [Pg.201]    [Pg.338]    [Pg.360]    [Pg.180]    [Pg.217]    [Pg.221]    [Pg.668]    [Pg.677]    [Pg.680]    [Pg.687]    [Pg.769]    [Pg.770]    [Pg.79]    [Pg.36]    [Pg.764]    [Pg.2461]    [Pg.2484]    [Pg.2493]   
See also in sourсe #XX -- [ Pg.624 ]




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Heisenberg spin chain

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Spin-labeled side chains

The Supply Chain Spin

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