scholarly journals Conditional Action and Imperfect Erasure of Qubits

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 289
Author(s):  
Heinz-Jürgen Schmidt
Keyword(s):  
Quantum Theory ◽  
Spin System ◽  
Ground State ◽  
Mathematical Theory ◽  
State Changes ◽  
Special Case ◽  
Changes Of State

We consider state changes in quantum theory due to “conditional action” and relate these to the discussion of entropy decrease due to interventions of “intelligent beings” and the principles of Szilard and Landauer/Bennett. The mathematical theory of conditional actions is a special case of the theory of “instruments”, which describes changes of state due to general measurements and will therefore be briefly outlined in the present paper. As a detailed example, we consider the imperfect erasure of a qubit that can also be viewed as a conditional action and will be realized by the coupling of a spin to another small spin system in its ground state.

Functional Quantum Theory of Free Relativistic Fermi Fields

1970 ◽  
Vol 25 (5) ◽  
pp. 575-586
Author(s):  
H. Stumpf
Keyword(s):  
Hilbert Space ◽  
Quantum Theory ◽  
Physical Interpretation ◽  
Functional Equations ◽  
Dirac Field ◽  
Functional Hilbert Space ◽  
Free Fermi ◽  
Special Case ◽  
Relativistic Fermi

Functional quantum theory of free Fermi fields is treated for the special case of a free Dirac field. All other cases run on the same pattern. Starting with the Schwinger functionals of the free Dirac field, functional equations and corresponding many particle functionals can be derived. To establish a functional quantum theory, a physical interpretation of the functionals is required. It is provided by a mapping of the physical Hilbert space into an appropriate functional Hilbert space, which is introduced here. Mathematical details, especially the problems connected with anticommuting functional sources are treated in the appendices.

Mental Phenomena as Changes of State in a Finite-State Machine

1986 ◽  
Vol 20 (2) ◽  
pp. 158-165 ◽  
Author(s):  
R. R. Kydd ◽  
J. J. Wright
Keyword(s):  
Finite State Machine ◽  
Conscious Experience ◽  
State Machine ◽  
Alternative Approach ◽  
Finite State ◽  
Biological Substrate ◽  
State Changes ◽  
Fundamental Unity ◽  
Mental Pathology ◽  
Changes Of State

This paper examines the classical functions of the psyche—cognition, affection and conation—from a phenomenological viewpoint and finds them to be defined each in terms of the other. It is held that this circularity of definition reflects the fundamental unity of conscious experience and, as a consequence, that the search for the biological substrate underlying individual functions too readily degenerates into a morphological and biochemical phrenology. An alternative approach, based on considerations from the field of artificial intelligence, is discussed. This approach provides a description of mental phenomena as changes of state in a finite-state machine, the next state being determined by both previous states and current inputs. This concept is shown to be compatible with the descriptions of conscious experience outlined in the phenomenology of Karl Jaspers. It is suggested that neurobiological investigations should be directed towards defining the processes by which state changes occur and further seeking to define mental pathology as aberrations of these dynamic processes.

scholarly journals Ground state changes induced by Ni substitution in NaxCoO2

2006 ◽  
Vol 138 (10-11) ◽  
pp. 489-493 ◽  
Author(s):  
N. Gayathri ◽  
A. Bharathi ◽  
V.S. Sastry ◽  
C.S. Sundar ◽  
Y. Hariharan
Keyword(s):  
Ground State ◽  
State Changes ◽  
Ni Substitution

The quantum theory of lattice dynamics. Il

1969 ◽  
Vol 310 (1500) ◽  
pp. 89-99 ◽  
Keyword(s):  
Quantum Theory ◽  
Total Energy ◽  
Ground State ◽  
Lattice Dynamics ◽  
Equilibrium Configuration ◽  
Third Order ◽  
Hartree Fock

Expressions are derived for the expansion of the total energy of the electrons in their ground state in a crystal in powers of displacements of the nuclei from their equilibrium configuration. The expansion is taken up to third order on the basis of the coupled Hartree-Fock equations and thus one obtains expressions for the electronic contributions to the dynamical and anharmonic tensors.

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