Fluctuation relation for heat exchange in Markovian open quantum systems.

A fluctuation relation for the heat exchange of an open quantum system under a thermalizing Markovian dynamics is derived. We show that the probability that the system absorbs an amount of heat from its bath, at a given time interval, divided by the probability of the reverse process (releasing the same amount of heat to the bath) is given by an exponential factor which depends on the amount of heat and the difference between the temperatures of the system and the bath. Interestingly, this relation is akin to the standard form of the fluctuation relation (for forward-backward dynamics). We also argue that the probability of the violation of the second law of thermodynamics in the form of the Clausius statement (i.e., net heat transfer from a cold system to its hot bath) drops exponentially with both the amount of heat and the temperature differences of the baths.

Entropy production and non-Markovian dynamical maps.

In the weak-coupling limit approach to open quantum systems, the presence of the bath is eliminated and accounted for by a master equation that introduces dissipative contributions to the system reduced dynamics: within this framework, there are no bath entropy contributions to the entropy balance. We show that, as a consequence, the entropy production fails to be positive for a class of physically legitimate, that is completely positive and trace preserving, non-Markovian dynamical maps. Moreover, in absence of the semigroup property, if the reduced dynamics has a thermal asymptotic state, this need not be stationary. Then even the integrated entropy production becomes negative. These observations imply that, when the conditions leading to reduced dynamics of semigroup type are relaxed, a consistent formulation of the second law of thermodynamics requires that the environment contribution to the entropy balance be explicitly taken into account.

Correlations in quantum thermodynamics: Heat, work, and entropy production.

We provide a characterization of energy in the form of exchanged heat and work between two interacting constituents of a closed, bipartite, correlated quantum system. By defining a binding energy we derive a consistent quantum formulation of the first law of thermodynamics, in which the role of correlations becomes evident, and this formulation reduces to the standard classical picture in relevant systems. We next discuss the emergence of the second law of thermodynamics under certain-but fairly general-conditions such as the Markovian assumption. We illustrate the role of correlations and interactions in thermodynamics through two examples.

Characterization of topological phases in the compass ladder model.

The phase diagram of the quantum compass ladder model is investigated through numerical density matrix renormalization group based on infinite matrix product state algorithm and analytic effective perturbation theory. For this model we obtain two symmetry-protected topological phases, protected by a Z2 × Z2 symmetry, and a topologically-trivial Z2-symmetry-breaking phase. The symmetry-protected topological phases--labeled by symmetry fractionalization--belong to different topological classes, where the complex-conjugate symmetry uniquely distinguishes them. An important result of this classification is that, as revealed by the nature of the Z2-symmetry-breaking phase, the associated quantum phase transitions are accompanied by an explicit symmetry breaking, and thus a local-order parameter conclusively identifies the phase diagram of the underlying model. This is in stark contrast to previous studies which require a non-local string order parameter to distinguish the corresponding quantum phase transitions. We numerically examine our results and show that the local-order parameter is related to the magnetization exponent 0.12 ± 0.01.

Quantum phase transitions in the Kondo-necklace model: perturbative continuous unitary transformation approach.

The Kondo-necklace model can describe magnetic low-energy limit of strongly correlated heavy fermion materials. There exist multiple energy scales in this model corresponding to each phase of the system. Here, we study quantum phase transition between the Kondo-singlet phase and the antiferromagnetic long-range ordered phase, and show the effect of anisotropies in terms of quantum information properties and vanishing energy gap. We employ the 'perturbative continuous unitary transformations' approach to calculate the energy gap and spin-spin correlations for the model in the thermodynamic limit of one, two, and three spatial dimensions as well as for spin ladders. In particular, we show that the method, although being perturbative, can predict the expected quantum critical point, where the gap of low-energy spectrum vanishes, which is in good agreement with results of other numerical and Green's function analyses. In addition, we employ concurrence, a bipartite entanglement measure, to study the criticality of the model. Absence of singularities in the derivative of concurrence in two and three dimensions in the Kondo-necklace model shows that this model features multipartite entanglement. We also discuss crossover from the one-dimensional to the two-dimensional model via the ladder structure.

Symmetry fractionalization: symmetry-protected topological phases of the bond-alternating spin-1/2 Heisenberg chain.

We study different phases of the one-dimensional bond-alternating spin-1/2 Heisenberg model by using the symmetry fractionalization mechanism. We employ the infinite matrix-product state representation of the ground state (through the infinite-size density matrix renormalization group algorithm) to obtain inequivalent projective representations and commutation relations of the (unbroken) symmetry groups of the model, which are used to identify the different phases. We find that the model exhibits trivial as well as symmetry-protected topological phases. The symmetry-protected topological phases are Haldane phases on even/odd bonds, which are protected by the time-reversal (acting on the spin as σ → -σ), parity (permutation of the chain about a specific bond), and dihedral (π-rotations about a pair of orthogonal axes) symmetries. Additionally, we investigate the phases of the most general two-body bond-alternating spin-1/2 model, which respects the time-reversal, parity, and dihedral symmetries, and obtain its corresponding twelve different types of the symmetry-protected topological phases.

Quantum metrology in open systems: dissipative Cramér-Rao bound.

Estimation of parameters is a pivotal task throughout science and technology. The quantum Cramér-Rao bound provides a fundamental limit of precision allowed to be achieved under quantum theory. For closed quantum systems, it has been shown how the estimation precision depends on the underlying dynamics. Here, we propose a general formulation for metrology scenarios in open quantum systems, aiming to relate the precision more directly to properties of the underlying dynamics. This feature may be employed to enhance an estimation precision, e.g., by quantum control techniques. Specifically, we derive a Cramér-Rao bound for a fairly large class of open system dynamics, which is governed by a (time-dependent) dynamical semigroup map. We illustrate the utility of this scenario through three examples.

Zeno effect for quantum computation and control.

It is well known that the quantum Zeno effect can protect specific quantum states from decoherence by using projective measurements. Here we combine the theory of weak measurements with stabilizer quantum error correction and detection codes. We derive rigorous performance bounds which demonstrate that the Zeno effect can be used to protect appropriately encoded arbitrary states to arbitrary accuracy while at the same time allowing for universal quantum computation or quantum control.

Quantum adiabatic brachistochrone.

We formulate a time-optimal approach to adiabatic quantum computation (AQC). A corresponding natural Riemannian metric is also derived, through which AQC can be understood as the problem of finding a geodesic on the manifold of control parameters. This geometrization of AQC is demonstrated through two examples, where we show that it leads to improved performance of AQC, and sheds light on the roles of entanglement and curvature of the control manifold in algorithmic performance.

A preliminary study on normal electrocardiographic parameters of ostriches (Struthio camelus).

Electrocardiograms were taken from 100 normal healthy male and female ostriches which were 1 to 15 months old using a base apex lead. The heart rate of those less than 3 months old ranged from 107 to 250 beats per minute with a mean of 171.47 +/- 9.03 and that of ostriches of more than 3 months old ranged from 43 to 167 with a mean of 90.52 +/- 2.64 beats/minute. The P-waves were positive in all cases except in 1 ostrich which it was isoelectric. The ORS complexes were mainly negative and either monophasic (QS) or biphasic (rS or RS). The T-wave showed more variation than other waves. The durations of P P-R, QRS, Q-T and T-waves of chicks and of those more than 3 months of age (4-15-month-old) were 0.04 +/- 0.00, 0.06 +/- 0.00; 0.14 +/- 0.04, 0.16 +/- 0.00; 0.04 +/- 0.00, 0.06 +/- 0.00; 0.18 +/- 0.00, 0.27 +/- 0.00 and 0.06 +/- 0.00, 0.09 +/- 0.01 s, respectively, and amplitudes of the main direction of P-, QRS and T- waves of 2 groups were 0.29 +/- 0.02, 0.26 +/- 0.01; 1.87 +/- 0.17, 2.21 +/- 0.08; and 0.34 +/- 0.06, 0.37 +/- 0.02 mV, respectively. Ten cases showed cardiac dysrhythmias of which 9 showed sinus arrhythmia and 1 showed premature atrial contractions (PAC). This study showed that the base apex lead can be a suitable monitoring lead for electrocardiographic examination of ostriches.

Physical, biochemical and cytologic properties of blood and synovial fluid in clinically normal adult camel (Camelus dromedarius).

Forty-three adult one-humped Iranian camels (Camelus dromedarius) were studied to determine their physical, cellular and biochemical parameters of synovial fluid and blood. All the animals were clinically normal with no clinical signs of locomotion problem. Synovial fluid samples were taken from both elbow joints, and blood samples were also obtained from the jugular vein immediately prior to arthrocentesis. The synovial fluid appeared pale, creamy, and clear with no debris. No clot formation was observed at room temperature. Mucin clot test in all samples was normal. The percentage of neutrophils and eosinophils in the synovial fluid was lower than that in blood (P < 0.05). In contrast, the percentage of lymphocytes and monocytes in the synovial fluid was higher than that in blood (P < 0.05). The concentration of protein, glucose, uric acid, inorganic phosphorus, calcium, sodium, potassium, magnesium and the activities of AST, ALT, ALP, CK and LDH was higher in the serum than in the synovial fluid (P < 0.05). Nonetheless, the concentration of chloride in the synovial fluid was higher than in the serum (P < 0.05). The concentration of urea nitrogen in the synovial fluid was similar to that of the serum. Comparing the values of the synovial fluid constituents of the left and the right elbow joint showed that there was no significant difference in any of the physical, cellular and biochemical parameters. No significant difference was found in any of the cellular and biochemical parameters of male and female camels' blood except in red blood cell counts, which was lower in females than in males. Comparing the values of the synovial fluid of male and female camels showed that there was no significant difference in any of the physical, cellular and biochemical parameters.

Evaluation of hematological, serum biochemical and cerebrospinal fluid parameters in experimental bacterial meningitis in the calf.

To evaluate the effects of bacterial meningitis on blood and CSF parameters, an experiment was conducted with five Iranian crossbred male calves. Blood and CSF samples were collected 3 times within a 5-day interval before the administration of bacteria for obtaining control values. Following the injection of E. coli, K12 into the cerebrospinal fluid from the lumbosacral space, samples were collected and clinical signs of meningitis were observed. Blood and CSF samples were obtained from the meningitis group 3 times at 1, 3, and 5 days post injection. The treatment of the infected calves using lincospectin and tetracycline was carried out immediately after the onset of clinical signs. After the treatment, blood and CSF samples were obtained 3 times during a 5-day period. Following the induction of meningitis, the number of WBCs, neutrophils, eosinophils and monocytes significantly increased (P < 0.05). However, the percent of lymphocytes decreased significantly (P < 0.05). The concentrations of glucose, potassium and activity of AST, LDH, CK significantly increased (P < 0.05). In contrast, the concentrations of phosphorous, sodium and magnesium significantly decreased (P < 0.05). Furthermore, following the induction of meningitis, the CSF was slightly xantochromic and turbid. The concentrations of protein, cholesterol, phosphorous, potassium, the activities of AST, LDH, CK, and the cell numbers in the CSF increased significantly (P < 0.05). In contrast, the concentration of glucose and pH in the CSF decreased significantly (P < 0.05). This study showed that bacterial meningitis can have profound effects on blood and CSF parameters which enable one to reach diagnosis.

Morphological studies on experimental oleander poisoning in cattle.

Oleander poisoning has been reported in man and animals. The present experiments address the gross and microscopic changes due to oleander poisoning in cattle. Minimum lethal doses (50 mg/kg) of oleander leaves were orally administered to three calves in a single dose each of the other three animals received the same lethal dose in three equal parts with 24-h intervals. The lesions in the three animals which received 50 mg/kg in a single dose resulted from the direct effect of the toxin on the vascular endothelial bed and demonstrated as petechial and diffused haemorrhages, congestion, oedema, cell degeneration and inflammatory cell infiltration in the lungs, heart, mesentry, kidneys, serosal and mucosal surfaces of omasum, abomasum and the intestine. The lungs also showed atelectasis, emphysema and disseminated intravascular coagulation. On the other hand, the animals which received divided doses showed lesions due to long-term exposure to the toxic agent and/or as the result of tissue ischaemia. The lungs also showed cell necrosis and mononuclear cell infiltration in the interstitial tissue, and some of the cardiac muscle fibres rather showed fibromyolysis and cell infiltration between muscle fibres, epicardium and endocardium. The intestinal villi showed haemorrhagic, degenerative and necrotic changes and the eosinophils were infiltrated in mucosal and submucosal layers of this organ. Multifocal degenerative and necrotic changes with inflammatory cell infiltration were also present in the liver parenchyma.

An atypical case of actinobacillosis in a cow.

An atypical case of actinobacillosis with involvement of the skin of the right hind limb and its lymphatics was diagnosed in a cow. The granulomatous lesions were observed as several masses along the lateral part of the right hind limb. The right precrural lymph node was enlarged more than 10 times its normal size. Histopathological examination of biopsy materials revealed actinobacillus granuloma. Smears of granular pus obtained from the precrural lymph node showed a small number of gram negative bacilli.