switching to high quality piper tts and added label translations

2026-01-29 23:48:19 +01:00
commit d80c619df9
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+"""Hilbert spaces for quantum mechanics.
+
+Authors:
+* Brian Granger
+* Matt Curry
+"""
+
+from functools import reduce
+
+from sympy.core.basic import Basic
+from sympy.core.singleton import S
+from sympy.core.sympify import sympify
+from sympy.sets.sets import Interval
+from sympy.printing.pretty.stringpict import prettyForm
+from sympy.physics.quantum.qexpr import QuantumError
+
+
+__all__ = [
+    'HilbertSpaceError',
+    'HilbertSpace',
+    'TensorProductHilbertSpace',
+    'TensorPowerHilbertSpace',
+    'DirectSumHilbertSpace',
+    'ComplexSpace',
+    'L2',
+    'FockSpace'
+]
+
+#-----------------------------------------------------------------------------
+# Main objects
+#-----------------------------------------------------------------------------
+
+
+class HilbertSpaceError(QuantumError):
+    pass
+
+#-----------------------------------------------------------------------------
+# Main objects
+#-----------------------------------------------------------------------------
+
+
+class HilbertSpace(Basic):
+    """An abstract Hilbert space for quantum mechanics.
+
+    In short, a Hilbert space is an abstract vector space that is complete
+    with inner products defined [1]_.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.quantum.hilbert import HilbertSpace
+    >>> hs = HilbertSpace()
+    >>> hs
+    H
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Hilbert_space
+    """
+
+    def __new__(cls):
+        obj = Basic.__new__(cls)
+        return obj
+
+    @property
+    def dimension(self):
+        """Return the Hilbert dimension of the space."""
+        raise NotImplementedError('This Hilbert space has no dimension.')
+
+    def __add__(self, other):
+        return DirectSumHilbertSpace(self, other)
+
+    def __radd__(self, other):
+        return DirectSumHilbertSpace(other, self)
+
+    def __mul__(self, other):
+        return TensorProductHilbertSpace(self, other)
+
+    def __rmul__(self, other):
+        return TensorProductHilbertSpace(other, self)
+
+    def __pow__(self, other, mod=None):
+        if mod is not None:
+            raise ValueError('The third argument to __pow__ is not supported \
+            for Hilbert spaces.')
+        return TensorPowerHilbertSpace(self, other)
+
+    def __contains__(self, other):
+        """Is the operator or state in this Hilbert space.
+
+        This is checked by comparing the classes of the Hilbert spaces, not
+        the instances. This is to allow Hilbert Spaces with symbolic
+        dimensions.
+        """
+        if other.hilbert_space.__class__ == self.__class__:
+            return True
+        else:
+            return False
+
+    def _sympystr(self, printer, *args):
+        return 'H'
+
+    def _pretty(self, printer, *args):
+        ustr = '\N{LATIN CAPITAL LETTER H}'
+        return prettyForm(ustr)
+
+    def _latex(self, printer, *args):
+        return r'\mathcal{H}'
+
+
+class ComplexSpace(HilbertSpace):
+    """Finite dimensional Hilbert space of complex vectors.
+
+    The elements of this Hilbert space are n-dimensional complex valued
+    vectors with the usual inner product that takes the complex conjugate
+    of the vector on the right.
+
+    A classic example of this type of Hilbert space is spin-1/2, which is
+    ``ComplexSpace(2)``. Generalizing to spin-s, the space is
+    ``ComplexSpace(2*s+1)``.  Quantum computing with N qubits is done with the
+    direct product space ``ComplexSpace(2)**N``.
+
+    Examples
+    ========
+
+    >>> from sympy import symbols
+    >>> from sympy.physics.quantum.hilbert import ComplexSpace
+    >>> c1 = ComplexSpace(2)
+    >>> c1
+    C(2)
+    >>> c1.dimension
+    2
+
+    >>> n = symbols('n')
+    >>> c2 = ComplexSpace(n)
+    >>> c2
+    C(n)
+    >>> c2.dimension
+    n
+
+    """
+
+    def __new__(cls, dimension):
+        dimension = sympify(dimension)
+        r = cls.eval(dimension)
+        if isinstance(r, Basic):
+            return r
+        obj = Basic.__new__(cls, dimension)
+        return obj
+
+    @classmethod
+    def eval(cls, dimension):
+        if len(dimension.atoms()) == 1:
+            if not (dimension.is_Integer and dimension > 0 or dimension is S.Infinity
+            or dimension.is_Symbol):
+                raise TypeError('The dimension of a ComplexSpace can only'
+                                'be a positive integer, oo, or a Symbol: %r'
+                                % dimension)
+        else:
+            for dim in dimension.atoms():
+                if not (dim.is_Integer or dim is S.Infinity or dim.is_Symbol):
+                    raise TypeError('The dimension of a ComplexSpace can only'
+                                    ' contain integers, oo, or a Symbol: %r'
+                                    % dim)
+
+    @property
+    def dimension(self):
+        return self.args[0]
+
+    def _sympyrepr(self, printer, *args):
+        return "%s(%s)" % (self.__class__.__name__,
+                           printer._print(self.dimension, *args))
+
+    def _sympystr(self, printer, *args):
+        return "C(%s)" % printer._print(self.dimension, *args)
+
+    def _pretty(self, printer, *args):
+        ustr = '\N{LATIN CAPITAL LETTER C}'
+        pform_exp = printer._print(self.dimension, *args)
+        pform_base = prettyForm(ustr)
+        return pform_base**pform_exp
+
+    def _latex(self, printer, *args):
+        return r'\mathcal{C}^{%s}' % printer._print(self.dimension, *args)
+
+
+class L2(HilbertSpace):
+    """The Hilbert space of square integrable functions on an interval.
+
+    An L2 object takes in a single SymPy Interval argument which represents
+    the interval its functions (vectors) are defined on.
+
+    Examples
+    ========
+
+    >>> from sympy import Interval, oo
+    >>> from sympy.physics.quantum.hilbert import L2
+    >>> hs = L2(Interval(0,oo))
+    >>> hs
+    L2(Interval(0, oo))
+    >>> hs.dimension
+    oo
+    >>> hs.interval
+    Interval(0, oo)
+
+    """
+
+    def __new__(cls, interval):
+        if not isinstance(interval, Interval):
+            raise TypeError('L2 interval must be an Interval instance: %r'
+            % interval)
+        obj = Basic.__new__(cls, interval)
+        return obj
+
+    @property
+    def dimension(self):
+        return S.Infinity
+
+    @property
+    def interval(self):
+        return self.args[0]
+
+    def _sympyrepr(self, printer, *args):
+        return "L2(%s)" % printer._print(self.interval, *args)
+
+    def _sympystr(self, printer, *args):
+        return "L2(%s)" % printer._print(self.interval, *args)
+
+    def _pretty(self, printer, *args):
+        pform_exp = prettyForm('2')
+        pform_base = prettyForm('L')
+        return pform_base**pform_exp
+
+    def _latex(self, printer, *args):
+        interval = printer._print(self.interval, *args)
+        return r'{\mathcal{L}^2}\left( %s \right)' % interval
+
+
+class FockSpace(HilbertSpace):
+    """The Hilbert space for second quantization.
+
+    Technically, this Hilbert space is a infinite direct sum of direct
+    products of single particle Hilbert spaces [1]_. This is a mess, so we have
+    a class to represent it directly.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.quantum.hilbert import FockSpace
+    >>> hs = FockSpace()
+    >>> hs
+    F
+    >>> hs.dimension
+    oo
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Fock_space
+    """
+
+    def __new__(cls):
+        obj = Basic.__new__(cls)
+        return obj
+
+    @property
+    def dimension(self):
+        return S.Infinity
+
+    def _sympyrepr(self, printer, *args):
+        return "FockSpace()"
+
+    def _sympystr(self, printer, *args):
+        return "F"
+
+    def _pretty(self, printer, *args):
+        ustr = '\N{LATIN CAPITAL LETTER F}'
+        return prettyForm(ustr)
+
+    def _latex(self, printer, *args):
+        return r'\mathcal{F}'
+
+
+class TensorProductHilbertSpace(HilbertSpace):
+    """A tensor product of Hilbert spaces [1]_.
+
+    The tensor product between Hilbert spaces is represented by the
+    operator ``*`` Products of the same Hilbert space will be combined into
+    tensor powers.
+
+    A ``TensorProductHilbertSpace`` object takes in an arbitrary number of
+    ``HilbertSpace`` objects as its arguments. In addition, multiplication of
+    ``HilbertSpace`` objects will automatically return this tensor product
+    object.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
+    >>> from sympy import symbols
+
+    >>> c = ComplexSpace(2)
+    >>> f = FockSpace()
+    >>> hs = c*f
+    >>> hs
+    C(2)*F
+    >>> hs.dimension
+    oo
+    >>> hs.spaces
+    (C(2), F)
+
+    >>> c1 = ComplexSpace(2)
+    >>> n = symbols('n')
+    >>> c2 = ComplexSpace(n)
+    >>> hs = c1*c2
+    >>> hs
+    C(2)*C(n)
+    >>> hs.dimension
+    2*n
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Hilbert_space#Tensor_products
+    """
+
+    def __new__(cls, *args):
+        r = cls.eval(args)
+        if isinstance(r, Basic):
+            return r
+        obj = Basic.__new__(cls, *args)
+        return obj
+
+    @classmethod
+    def eval(cls, args):
+        """Evaluates the direct product."""
+        new_args = []
+        recall = False
+        #flatten arguments
+        for arg in args:
+            if isinstance(arg, TensorProductHilbertSpace):
+                new_args.extend(arg.args)
+                recall = True
+            elif isinstance(arg, (HilbertSpace, TensorPowerHilbertSpace)):
+                new_args.append(arg)
+            else:
+                raise TypeError('Hilbert spaces can only be multiplied by \
+                other Hilbert spaces: %r' % arg)
+        #combine like arguments into direct powers
+        comb_args = []
+        prev_arg = None
+        for new_arg in new_args:
+            if prev_arg is not None:
+                if isinstance(new_arg, TensorPowerHilbertSpace) and \
+                    isinstance(prev_arg, TensorPowerHilbertSpace) and \
+                        new_arg.base == prev_arg.base:
+                    prev_arg = new_arg.base**(new_arg.exp + prev_arg.exp)
+                elif isinstance(new_arg, TensorPowerHilbertSpace) and \
+                        new_arg.base == prev_arg:
+                    prev_arg = prev_arg**(new_arg.exp + 1)
+                elif isinstance(prev_arg, TensorPowerHilbertSpace) and \
+                        new_arg == prev_arg.base:
+                    prev_arg = new_arg**(prev_arg.exp + 1)
+                elif new_arg == prev_arg:
+                    prev_arg = new_arg**2
+                else:
+                    comb_args.append(prev_arg)
+                    prev_arg = new_arg
+            elif prev_arg is None:
+                prev_arg = new_arg
+        comb_args.append(prev_arg)
+        if recall:
+            return TensorProductHilbertSpace(*comb_args)
+        elif len(comb_args) == 1:
+            return TensorPowerHilbertSpace(comb_args[0].base, comb_args[0].exp)
+        else:
+            return None
+
+    @property
+    def dimension(self):
+        arg_list = [arg.dimension for arg in self.args]
+        if S.Infinity in arg_list:
+            return S.Infinity
+        else:
+            return reduce(lambda x, y: x*y, arg_list)
+
+    @property
+    def spaces(self):
+        """A tuple of the Hilbert spaces in this tensor product."""
+        return self.args
+
+    def _spaces_printer(self, printer, *args):
+        spaces_strs = []
+        for arg in self.args:
+            s = printer._print(arg, *args)
+            if isinstance(arg, DirectSumHilbertSpace):
+                s = '(%s)' % s
+            spaces_strs.append(s)
+        return spaces_strs
+
+    def _sympyrepr(self, printer, *args):
+        spaces_reprs = self._spaces_printer(printer, *args)
+        return "TensorProductHilbertSpace(%s)" % ','.join(spaces_reprs)
+
+    def _sympystr(self, printer, *args):
+        spaces_strs = self._spaces_printer(printer, *args)
+        return '*'.join(spaces_strs)
+
+    def _pretty(self, printer, *args):
+        length = len(self.args)
+        pform = printer._print('', *args)
+        for i in range(length):
+            next_pform = printer._print(self.args[i], *args)
+            if isinstance(self.args[i], (DirectSumHilbertSpace,
+                          TensorProductHilbertSpace)):
+                next_pform = prettyForm(
+                    *next_pform.parens(left='(', right=')')
+                )
+            pform = prettyForm(*pform.right(next_pform))
+            if i != length - 1:
+                if printer._use_unicode:
+                    pform = prettyForm(*pform.right(' ' + '\N{N-ARY CIRCLED TIMES OPERATOR}' + ' '))
+                else:
+                    pform = prettyForm(*pform.right(' x '))
+        return pform
+
+    def _latex(self, printer, *args):
+        length = len(self.args)
+        s = ''
+        for i in range(length):
+            arg_s = printer._print(self.args[i], *args)
+            if isinstance(self.args[i], (DirectSumHilbertSpace,
+                 TensorProductHilbertSpace)):
+                arg_s = r'\left(%s\right)' % arg_s
+            s = s + arg_s
+            if i != length - 1:
+                s = s + r'\otimes '
+        return s
+
+
+class DirectSumHilbertSpace(HilbertSpace):
+    """A direct sum of Hilbert spaces [1]_.
+
+    This class uses the ``+`` operator to represent direct sums between
+    different Hilbert spaces.
+
+    A ``DirectSumHilbertSpace`` object takes in an arbitrary number of
+    ``HilbertSpace`` objects as its arguments. Also, addition of
+    ``HilbertSpace`` objects will automatically return a direct sum object.
+
+    Examples
+    ========
+
+    >>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
+
+    >>> c = ComplexSpace(2)
+    >>> f = FockSpace()
+    >>> hs = c+f
+    >>> hs
+    C(2)+F
+    >>> hs.dimension
+    oo
+    >>> list(hs.spaces)
+    [C(2), F]
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Hilbert_space#Direct_sums
+    """
+    def __new__(cls, *args):
+        r = cls.eval(args)
+        if isinstance(r, Basic):
+            return r
+        obj = Basic.__new__(cls, *args)
+        return obj
+
+    @classmethod
+    def eval(cls, args):
+        """Evaluates the direct product."""
+        new_args = []
+        recall = False
+        #flatten arguments
+        for arg in args:
+            if isinstance(arg, DirectSumHilbertSpace):
+                new_args.extend(arg.args)
+                recall = True
+            elif isinstance(arg, HilbertSpace):
+                new_args.append(arg)
+            else:
+                raise TypeError('Hilbert spaces can only be summed with other \
+                Hilbert spaces: %r' % arg)
+        if recall:
+            return DirectSumHilbertSpace(*new_args)
+        else:
+            return None
+
+    @property
+    def dimension(self):
+        arg_list = [arg.dimension for arg in self.args]
+        if S.Infinity in arg_list:
+            return S.Infinity
+        else:
+            return reduce(lambda x, y: x + y, arg_list)
+
+    @property
+    def spaces(self):
+        """A tuple of the Hilbert spaces in this direct sum."""
+        return self.args
+
+    def _sympyrepr(self, printer, *args):
+        spaces_reprs = [printer._print(arg, *args) for arg in self.args]
+        return "DirectSumHilbertSpace(%s)" % ','.join(spaces_reprs)
+
+    def _sympystr(self, printer, *args):
+        spaces_strs = [printer._print(arg, *args) for arg in self.args]
+        return '+'.join(spaces_strs)
+
+    def _pretty(self, printer, *args):
+        length = len(self.args)
+        pform = printer._print('', *args)
+        for i in range(length):
+            next_pform = printer._print(self.args[i], *args)
+            if isinstance(self.args[i], (DirectSumHilbertSpace,
+                          TensorProductHilbertSpace)):
+                next_pform = prettyForm(
+                    *next_pform.parens(left='(', right=')')
+                )
+            pform = prettyForm(*pform.right(next_pform))
+            if i != length - 1:
+                if printer._use_unicode:
+                    pform = prettyForm(*pform.right(' \N{CIRCLED PLUS} '))
+                else:
+                    pform = prettyForm(*pform.right(' + '))
+        return pform
+
+    def _latex(self, printer, *args):
+        length = len(self.args)
+        s = ''
+        for i in range(length):
+            arg_s = printer._print(self.args[i], *args)
+            if isinstance(self.args[i], (DirectSumHilbertSpace,
+                 TensorProductHilbertSpace)):
+                arg_s = r'\left(%s\right)' % arg_s
+            s = s + arg_s
+            if i != length - 1:
+                s = s + r'\oplus '
+        return s
+
+
+class TensorPowerHilbertSpace(HilbertSpace):
+    """An exponentiated Hilbert space [1]_.
+
+    Tensor powers (repeated tensor products) are represented by the
+    operator ``**`` Identical Hilbert spaces that are multiplied together
+    will be automatically combined into a single tensor power object.
+
+    Any Hilbert space, product, or sum may be raised to a tensor power. The
+    ``TensorPowerHilbertSpace`` takes two arguments: the Hilbert space; and the
+    tensor power (number).
+
+    Examples
+    ========
+
+    >>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
+    >>> from sympy import symbols
+
+    >>> n = symbols('n')
+    >>> c = ComplexSpace(2)
+    >>> hs = c**n
+    >>> hs
+    C(2)**n
+    >>> hs.dimension
+    2**n
+
+    >>> c = ComplexSpace(2)
+    >>> c*c
+    C(2)**2
+    >>> f = FockSpace()
+    >>> c*f*f
+    C(2)*F**2
+
+    References
+    ==========
+
+    .. [1] https://en.wikipedia.org/wiki/Hilbert_space#Tensor_products
+    """
+
+    def __new__(cls, *args):
+        r = cls.eval(args)
+        if isinstance(r, Basic):
+            return r
+        return Basic.__new__(cls, *r)
+
+    @classmethod
+    def eval(cls, args):
+        new_args = args[0], sympify(args[1])
+        exp = new_args[1]
+        #simplify hs**1 -> hs
+        if exp is S.One:
+            return args[0]
+        #simplify hs**0 -> 1
+        if exp is S.Zero:
+            return S.One
+        #check (and allow) for hs**(x+42+y...) case
+        if len(exp.atoms()) == 1:
+            if not (exp.is_Integer and exp >= 0 or exp.is_Symbol):
+                raise ValueError('Hilbert spaces can only be raised to \
+                positive integers or Symbols: %r' % exp)
+        else:
+            for power in exp.atoms():
+                if not (power.is_Integer or power.is_Symbol):
+                    raise ValueError('Tensor powers can only contain integers \
+                    or Symbols: %r' % power)
+        return new_args
+
+    @property
+    def base(self):
+        return self.args[0]
+
+    @property
+    def exp(self):
+        return self.args[1]
+
+    @property
+    def dimension(self):
+        if self.base.dimension is S.Infinity:
+            return S.Infinity
+        else:
+            return self.base.dimension**self.exp
+
+    def _sympyrepr(self, printer, *args):
+        return "TensorPowerHilbertSpace(%s,%s)" % (printer._print(self.base,
+        *args), printer._print(self.exp, *args))
+
+    def _sympystr(self, printer, *args):
+        return "%s**%s" % (printer._print(self.base, *args),
+        printer._print(self.exp, *args))
+
+    def _pretty(self, printer, *args):
+        pform_exp = printer._print(self.exp, *args)
+        if printer._use_unicode:
+            pform_exp = prettyForm(*pform_exp.left(prettyForm('\N{N-ARY CIRCLED TIMES OPERATOR}')))
+        else:
+            pform_exp = prettyForm(*pform_exp.left(prettyForm('x')))
+        pform_base = printer._print(self.base, *args)
+        return pform_base**pform_exp
+
+    def _latex(self, printer, *args):
+        base = printer._print(self.base, *args)
+        exp = printer._print(self.exp, *args)
+        return r'{%s}^{\otimes %s}' % (base, exp)