A quantum metrology research engineer operates an Absolute Quantum Gravimeter, a mobile instrument which acts as a national reference for the measure of gravity, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

Quantum metrology research engineer Matthieu Thomas presents the Kibble balance, an electromechanical measuring instrument used to determine the definition of the kilogram unit of mass, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

This photograph taken on December 11, 2025, shows a partial view of the Kibble balance, an electromechanical measuring instrument used to determine the definition of the kilogram unit of mass, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

Quantum metrology research engineer Matthieu Thomas presents the Kibble balance, an electromechanical measuring instrument used to determine the definition of the kilogram unit of mass, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

Quantum metrology research engineer Francois Couedo presents measurement instruments, a quantum calculator from the laboratory of characterisation of solid-state Qubit and enabling technologies, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

Quantum metrology research engineer Francois Couedo presents measurement instruments, a quantum calculator from the laboratory of characterisation of solid-state Qubit and enabling technologies, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

Quantum metrology research engineer Matthieu Thomas presents the Kibble balance, an electromechanical measuring instrument used to determine the definition of the kilogram unit of mass, during the presentation of the MetriQs-France platform which provides reliable measurements for quantum technology, in Trappes southwest of Paris on December 11, 2025. (Photo by Anne-Christine POUJOULAT / AFP via Getty Images)

People ride a Ferris wheel in front of the Palace of Culture and Science at the Christmas market in Warsaw on December 11, 2025. (Photo by Sergei GAPON / AFP via Getty Images)