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Z. Zheng
4.1 Introduction
The core mission of physics is to understand basic laws of everything in the
universe. The Chinese vocabulary the English word “UNIVERSE” is “宇宙”, which
is composed of two characters “宇” and “宙” with distinctly different meanings.
The word “宇” means the space, and “宙” refers to the time. The ancient Chinese
philosopher Shi Jiao(尸佼, or 尸子, Shi Zi) in the Warring States period (475–221
B.C.), wrote that “四方上下曰宇, 往古来今曰宙” in his book “Shi Zi”. Similar
expressions also appeared in other books such as “Wen Zi: the Nature”, “Zhuang Zi.
Geng Sang Chu”, “Huai Nai Zi”, and so on [1]. These interesting citations indicate
that the mission of physicists is a deep understanding of basic laws of space and
time, or say, the common and fundamental laws of variations embedded in different
systems.
A basic paradigm of natural science developed throughout the past many decades
is the principle of reductionism. The essence of reductionism is that a system is
composed of many elements, with each element can be well understood and physically described. As long as the laws governing the elements are clear, it is expected
that the properties of the system can be well understood and reconstructed. This
belief had been successfully undertaken in the 18–19 centuries, where the structures
of matters, ranging from molecules, atoms, protons, neutrons, electrons to quarks,
were successfully revealed [2].
The reductionism encountered its crisis from the first half of the twentieth century.
The development of thermodynamics and statistical physics, especially the findings
of various phase transitions such as superconductivity and superfluidity, indicated
that these behaviors result from the collective macroscopic effect of molecules and
atoms, which do not occur at the atom/microscopic level. Physicists working on statistical physics interpreted the occurrence of phase transition as a symmetry breaking,
which can be extensively found in antiferromagnets, ferroelectrics, liquid crystals
and condensed matters in many other states. Philip Andersen connected the later
findings of quasiparticles, e.g. phonons, implies collective excitations and modes
organized by atoms with interactions [3]. Collective behaviors that are formed by
interacted units in a system, e.g. transitions among different phases, are termed as
the emergence.
The emergence property of many-body systems implies the collapse and failure
of reductionism. Andersen asserted:
The ability to reduce everything to simple fundamental laws does not imply the ability to
start from those laws and reconstruct the universe…… The behavior of large and complex
aggregates of elementary particles, it turns out, is not to be understood in terms of a simple
extrapolation of the properties of a few particles. Instead, at each level of complexity entirely
new properties appear, and the understanding of the new behaviors requires research which
I think is as fundamental in its nature as any other.
Nowadays, emergent behaviors have been extensively found in living activities
of neuron systems, brains and the formation of proteins, DNA, and genes [4]. These
phenomena imply that even if one knows everything about an element, the behaviors
Z. Zheng
4.1 Introduction
The core mission of physics is to understand basic laws of everything in the
universe. The Chinese vocabulary the English word “UNIVERSE” is “宇宙”, which
is composed of two characters “宇” and “宙” with distinctly different meanings.
The word “宇” means the space, and “宙” refers to the time. The ancient Chinese
philosopher Shi Jiao(尸佼, or 尸子, Shi Zi) in the Warring States period (475–221
B.C.), wrote that “四方上下曰宇, 往古来今曰宙” in his book “Shi Zi”. Similar
expressions also appeared in other books such as “Wen Zi: the Nature”, “Zhuang Zi.
Geng Sang Chu”, “Huai Nai Zi”, and so on [1]. These interesting citations indicate
that the mission of physicists is a deep understanding of basic laws of space and
time, or say, the common and fundamental laws of variations embedded in different
systems.
A basic paradigm of natural science developed throughout the past many decades
is the principle of reductionism. The essence of reductionism is that a system is
composed of many elements, with each element can be well understood and physically described. As long as the laws governing the elements are clear, it is expected
that the properties of the system can be well understood and reconstructed. This
belief had been successfully undertaken in the 18–19 centuries, where the structures
of matters, ranging from molecules, atoms, protons, neutrons, electrons to quarks,
were successfully revealed [2].
The reductionism encountered its crisis from the first half of the twentieth century.
The development of thermodynamics and statistical physics, especially the findings
of various phase transitions such as superconductivity and superfluidity, indicated
that these behaviors result from the collective macroscopic effect of molecules and
atoms, which do not occur at the atom/microscopic level. Physicists working on statistical physics interpreted the occurrence of phase transition as a symmetry breaking,
which can be extensively found in antiferromagnets, ferroelectrics, liquid crystals
and condensed matters in many other states. Philip Andersen connected the later
findings of quasiparticles, e.g. phonons, implies collective excitations and modes
organized by atoms with interactions [3]. Collective behaviors that are formed by
interacted units in a system, e.g. transitions among different phases, are termed as
the emergence.
The emergence property of many-body systems implies the collapse and failure
of reductionism. Andersen asserted:
The ability to reduce everything to simple fundamental laws does not imply the ability to
start from those laws and reconstruct the universe…… The behavior of large and complex
aggregates of elementary particles, it turns out, is not to be understood in terms of a simple
extrapolation of the properties of a few particles. Instead, at each level of complexity entirely
new properties appear, and the understanding of the new behaviors requires research which
I think is as fundamental in its nature as any other.
Nowadays, emergent behaviors have been extensively found in living activities
of neuron systems, brains and the formation of proteins, DNA, and genes [4]. These
phenomena imply that even if one knows everything about an element, the behaviors