QuantumInfo.Finite.CPTPMap.Bundled
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Underlying linear map of a Hermitian-preserving map
#mapLet be a Hermitian-preserving matrix map from matrices of dimension to matrices of dimension over a field . The function returns the underlying linear map associated with .
Extensionality of Hermitian-preserving maps
#extLet and be Hermitian-preserving matrix maps. If their underlying matrix mapping functions are equal (i.e., ), then the bundled maps and are equal.
Hermitian-preserving maps are equal if they agree on all Hermitian matrices
#funext_hermitianLet and be Hermitian-preserving matrix maps from matrices of dimension to matrices of dimension over . If for every Hermitian matrix of dimension , the maps agree such that , then the maps themselves are equal ().
Hermitian-preserving maps are equal if they agree on all positive semidefinite matrices
#funext_posLet and be hermitian-preserving matrix maps from to over . If for every hermitian matrix of dimension that is positive semidefinite (), the maps agree such that , then the maps themselves are equal ().
Hermitian-preserving maps are equal if they agree on all positive semidefinite matrices with trace one
#funext_pos_traceLet and be hermitian-preserving matrix maps from to over the complex numbers . If for every hermitian matrix of dimension that is both positive semidefinite () and has a trace equal to one (), the maps agree such that , then the maps themselves are equal ().
Hermitian-preserving maps are equal if they agree on all mixed states
#funext_mstateLet and be Hermitian-preserving matrix maps from matrices to matrices over the complex numbers . If for every mixed state of dimension , the maps agree on the underlying matrix representation of the state, such that , then the maps are equal (). (Here, a mixed state is a positive semidefinite Hermitian matrix with trace 1).
Function-like instance for Hermitian-preserving maps `HPMap`
#instFunLikeThe type `HPMap dIn dOut ℂ` of Hermitian-preserving maps is endowed with a function-like structure (`FunLike`). This allows an element to be treated as a function that maps a Hermitian matrix to a Hermitian matrix in . The value of this function is defined as , where is the underlying linear map on complex matrices.
Evaluation of an `HPMap` on a `HermitianMat` equals
#apply_hermitianMat_eqLet be a Hermitian-preserving map (an `HPMap`) from matrices to matrices over the complex numbers . Let be a Hermitian matrix of dimension (represented as a subtype consisting of a matrix and a proof of its Hermiticity). The application of to , denoted by , is equal to the Hermitian matrix whose underlying matrix is and whose proof of Hermiticity is .
Hermitian-preserving maps are continuous -linear maps between Hermitian matrix spaces
#instContinuousLinearMapClassComplexRealHermitianMatLet be a finite type (dimension index) and be a type. Let be the type of Hermitian-preserving linear maps between complex matrices of these dimensions. There exists an instance of `ContinuousLinearMapClass` for over the scalar field , treating the space of Hermitian matrices as a real vector space. This characterizes complex Hermitian-preserving maps as continuous -linear maps when restricted to the domain and codomain of Hermitian matrices.
Extensionality of positive-preserving maps (PMaps)
#extLet and be positive-preserving maps (of type `PMap`) from input dimension to output dimension over a field . If the underlying matrix maps associated with and are equal (i.e., ), then the positive-preserving maps themselves are equal ().
Injectivity of the conversion from positive-preserving maps to Hermitian-preserving maps
#injective_toHPMapLet and be finite types and be a field (typically or ). Consider the mapping `toHPMap` which casts a positive-preserving map (an element of `PMap`) to its underlying Hermitian-preserving map (an element of `HPMap`). This mapping is injective; that is, if two positive-preserving maps map to the same Hermitian-preserving map, they are identical.
is a function type from to
#instFunLikeThe type of positive-preserving maps between complex matrices of dimensions and behaves like a type of functions. It maps a Hermitian matrix to another Hermitian matrix . This is implemented by composing the coercion of its underlying Hermitian-preserving map with the conversion from a positive-preserving map.
Evaluation of a Positive-Preserving Map on a Hermitian Matrix
#apply_hermitianMat_eqLet be a positive-preserving map (an element of `PMap`) between the spaces of matrices of dimensions and over the complex numbers . Let be a Hermitian matrix of dimension , represented as a subtype pair where is the underlying matrix and is the proof of its hermiticity. The application of the map to is equal to the Hermitian matrix whose underlying matrix is applied to , and whose hermiticity proof is given by the fact that is a Hermitian-preserving map ().
The type of positive-preserving maps is a -linear map class between Hermitian matrix spaces
#instLinearMapClassLet be the type of positive-preserving maps between matrices of dimension and over the complex numbers . These maps satisfy the properties of a linear map class over the real numbers , mapping the space of Hermitian matrices of dimension to the space of Hermitian matrices of dimension .
is a Class of Continuous Order Homomorphisms between Hermitian Matrix Spaces
#instContinuousOrderHomClassThe type of positive-preserving maps between spaces of complex matrices is an instance of a continuous order-preserving homomorphism class (`ContinuousOrderHomClass`). This means that for any such map , the induced function from the space of Hermitian matrices to is both continuous and monotonic with respect to the Loewner order (the partial order defined by positive semidefiniteness).
PMaps preserve positivity of Hermitian matrices
#pos_HermitianLet be a positive-preserving map (PMap) from complex matrices to complex matrices. For any Hermitian matrix of dimension such that is positive semidefinite (), the image is also positive semidefinite ().
Completely positive map from Kraus operators
#of_kraus_CPMapGiven a finite collection of matrices where each is a matrix of size over a field (typically ), the map defined by the Kraus representation is a completely positive map (CPMap) from matrices to matrices. Here, the underlying linear map is constructed using `MatrixMap.of_kraus`, and its complete positivity is guaranteed by the property that any map in Kraus form is completely positive.
Extensionality of PTP maps via their underlying linear maps
#extLet and be positive trace-preserving maps (PTP maps) between matrix spaces over a field . If the underlying linear maps associated with and are equal (i.e., ), then and are equal as PTP maps.
The map from PTP maps to P maps is injective
#injective_toPMapLet be the space of positive trace-preserving maps between matrix spaces over a field , and let be the space of positive-preserving maps. The canonical projection (or coercion) , which maps a positive trace-preserving map to its underlying positive-preserving map, is injective.
is a function type from to
#instFunLikeThe type of positive trace-preserving maps between complex matrices of dimensions and is equipped with an instance that allows it to behave as a type of functions. Specifically, it maps a Hermitian matrix to another Hermitian matrix . This function behavior is defined by composing the coercion of its underlying positive-preserving map () with the conversion from a positive trace-preserving map.
Agreement of and for Hermitian Matrices
#apply_hermitianMat_eq_toPMapLet be a positive trace-preserving map (PTP map) from input dimension to output dimension over the complex numbers . For any Hermitian matrix of dimension , the application of to is equal to the application of its underlying positive-preserving map (`toPMap`) to .
is a -linear map class between Hermitian matrix spaces
#instLinearMapClassLet be the type of positive trace-preserving maps between complex matrices of dimensions and . Then forms a class of -linear maps from the space of Hermitian matrices of dimension to the space of Hermitian matrices of dimension .
is a Continuous Order Homomorphism Class
#instHContinuousOrderHomClassThe type of positive trace-preserving maps () from the space of Hermitian matrices to Hermitian matrices over the complex numbers forms a class of continuous order-preserving homomorphisms. Specifically, every such map is continuous and monotone, meaning that for any Hermitian matrices , if (in the Loewner order), then .
PTP Maps preserve positivity of Hermitian matrices
#pos_HermitianLet be a positive trace-preserving (PTP) map from the space of Hermitian matrices of dimension to over the complex numbers . For any Hermitian matrix of dimension such that is positive semidefinite (), the result of applying the map is also positive semidefinite ().
`PTPMap` is a class of functions from `MState dIn` to `MState dOut`
#instMFunLikeThe structure of positive trace-preserving maps (`PTPMap`) from an input dimension to an output dimension acts as a type of functions between mixed states. Specifically, for any such map and any mixed state of dimension , the application is defined as the mixed state in dimension whose underlying Hermitian matrix is the image of the matrix of under the map. This mapping is well-defined because preserves both the positive semidefiniteness and the unit trace of the state, and it is injective relative to the underlying linear map.
The application of a PTP map to a mixed state preserves mixed state properties
#apply_mstate_eqLet be a positive trace-preserving map (PTP map) from input dimension to output dimension over the complex numbers . Let be a mixed state of dimension with associated Hermitian matrix (which is positive semidefinite and has trace 1). The application of the map to the mixed state , denoted , is the mixed state in dimension whose underlying matrix is obtained by applying the linear map part of to . This resulting state is well-defined because preserves both the positive semidefiniteness and the unit trace of the state.
Positive trace-preserving maps are continuous functions between mixed state spaces
#instMContinuousMapClassLet and be finite dimensional Hilbert space indices. The type of positive trace-preserving maps from input mixed states to output mixed states is an instance of `ContinuousMapClass`. This means that every positive trace-preserving map is continuous when viewed as a function between the topological spaces of mixed states and , where both spaces are equipped with the subspace topology inherited from the space of complex matrices.
The matrix of the PTP-transformed state equals
#val_apply_MStateLet be a positive trace-preserving (PTP) map from input dimension to output dimension over the complex numbers . Let be a mixed state (represented by an object of type `MState dIn`). The underlying Hermitian matrix of the mixed state resulting from the application is equal to the result of applying the map (coerced as a function) to the Hermitian matrix associated with .
If the input dimension of a PTP map is non-zero, then the output dimension is non-zero
#nonemptyOutLet be a positive trace-preserving (PTP) map from matrices to matrices. If the input index set is non-empty, then the output index set must also be non-empty.
Equality of Matrix Maps Implies for CPTP Maps
#extLet and be completely positive trace-preserving (CPTP) maps from input dimension to output dimension over the field . If the underlying linear matrix maps of and are equal, then .
The inclusion of CPTP maps into PTP maps is injective
#injective_toPTPMapLet be the set of completely positive trace-preserving linear maps and be the set of positive trace-preserving linear maps between matrix spaces of dimensions and over the field . The forgetful map , which treats a completely positive trace-preserving map as a positive trace-preserving map, is injective.
Function-like instance for maps between matrix states
#instMFunLikeFor a completely positive trace-preserving (CPTP) map from the space of density matrices (mixed states) to , the structure provides an instance of a function-like mapping. Specifically, for any such map , there is a corresponding function defined by its action on matrix states, ensuring that CPTP maps can be applied directly to states as mathematical functions.
Agreement of CPTP and PTP Map Application on Quantum States
#apply_mState_eq_toPTPMapLet be a completely positive trace-preserving (CPTP) map from input dimension to output dimension . For any density matrix (quantum state) of dimension , the application of to is equal to the application of its underlying positive trace-preserving (PTP) map to . That is, .
The underlying map of a CPTP map is trace-preserving
#IsTracePreservingLet be a completely positive trace-preserving (CPTP) map from matrices to matrices over the field . Then its underlying linear map is trace-preserving.
Construction of a CPTP map from Kraus operators satisfying
#of_kraus_CPTPMapGiven a finite family of matrices where each satisfies the completeness relation , this definition constructs a completely positive trace-preserving (CPTP) map from to . The map is defined via the Kraus representation .
Extensionality of positive unital maps (PUMaps)
#extLet and be positive unital maps (of type `PUMap`) from input dimension to output dimension over a field . If the underlying matrix maps associated with and are equal (i.e., ), then the positive unital maps themselves are equal ().
Injectivity of the Forgetful Mapping from Positive Unital Maps to Positive Maps
#injective_toPMapThe function `PUMap.toPMap`, which sends a positive unital map to its underlying positive map, is injective. That is, for any two positive unital maps and between matrix spaces over the field , if their underlying positive maps are equal, then .
acts as a function from to
#instFunLikePositive Unital Maps () from the space of complex Hermitian matrices to complex Hermitian matrices can be treated as functions. Specifically, for any such map , its application to a Hermitian matrix is defined by the action of its underlying positive map.
for Positive Unital Maps
#apply_hermitianMat_eq_toPMapLet be a positive unital map between complex matrix spaces, and let be a Hermitian matrix. The application of the positive unital map to is equal to the application of its underlying positive map to .
Positive Unital Maps are -Linear Maps between Hermitian Matrix Spaces
#instLinearMapClassThe type of positive unital maps from complex matrices to complex matrices, denoted as , satisfies the `LinearMapClass` requirements. Specifically, any such map acts as an -linear map between the spaces of matrices and .
are Continuous Order Homomorphisms between Hermitian Matrix Spaces
#instHContinuousOrderHomClassLet be the space of positive unital maps from complex matrices to complex matrices. Any such map is a continuous order-preserving homomorphism from the space of Hermitian matrices to . This implies that is continuous with respect to the matrix topologies and satisfies for any Hermitian matrices .
Positive Unital Maps Preserve the Identity Matrix
#instOneHomClassLet be the space of positive unital maps from complex matrices to complex matrices. Any such map is a "one-preserving homomorphism" between the spaces of Hermitian matrices and . Specifically, maps the identity matrix to the identity matrix (i.e., ).
Positive Unital Maps Preserve Positivity of Hermitian Matrices
#pos_HermitianLet be a positive unital map from the space of complex matrices to complex matrices. For any Hermitian matrix of size such that is positive semidefinite (), its image under the map is also positive semidefinite ().
Extensionality of completely positive unital maps (CPUMaps)
#extLet and be completely positive unital maps (of type `CPUMap`) from input dimension to output dimension over a field . If the underlying linear maps associated with and are equal (i.e., ), then the completely positive unital maps themselves are equal ().
The map is injective
#injective_toPMapThe composition of the forgetful map from completely positive unital maps () to completely positive maps () and the forgetful map from completely positive maps to positive-preserving maps () is injective. In other words, a completely positive unital map is uniquely determined by its underlying positive-preserving map.
is a function type from to
#instFunLikeThe type of completely positive unital maps, denoted as , acts as a space of functions. Specifically, each element in this type maps a Hermitian matrix to a Hermitian matrix . This functional behavior is realized through the coercion to its underlying positive-preserving map ().
Agreement of CPUMap and PMap actions on Hermitian matrices
#apply_hermitianMat_eq_toPMapLet be a completely positive unital map (CPUMap) from input dimension to output dimension over the complex numbers . For any Hermitian matrix of dimension over , the action of on is equal to the action of its underlying positive-preserving map (PMap) on .
The type of completely positive unital maps is a -linear map class between Hermitian matrix spaces
#instLinearMapClassLet denote the type of completely positive unital maps between complex matrix spaces of dimensions and . This type forms a linear map class over the real numbers , acting between the space of complex Hermitian matrices and the space of complex Hermitian matrices.
Completely positive unital maps are continuous order-preserving homomorphisms
#instHContinuousOrderHomClassThe type of completely positive unital maps from complex Hermitian matrices to complex Hermitian matrices, denoted as `CPUMap dIn dOut ℂ`, satisfies the `ContinuousOrderHomClass` predicates. This means that every such map is a continuous function between the spaces of Hermitian matrices that preserves the partial ordering defined on these matrices.
Completely positive unital maps preserve the identity matrix
#instOneHomClassThe type of completely positive unital maps, denoted as `CPUMap dIn dOut ℂ`, which maps complex Hermitian matrices of dimension to those of dimension , satisfies the `OneHomClass` predicate. This means that any map in this class preserves the identity element, specifically , where denotes the identity matrix (the "one" element in the space of Hermitian matrices).
Completely positive unital maps preserve the positivity of Hermitian matrices
#pos_HermitianLet be a completely positive unital map from the space of complex Hermitian matrices to the space of complex Hermitian matrices. For any Hermitian matrix , if is positive semi-definite (i.e., ), then its image is also positive semi-definite (i.e., ).
