Tate Britain, London, 12 April – 29 August
Reacting against the optical experience offered by Abstract Expressionist painting after the war, conceptual artists in the 1960s gave precedence to ideas over art objects. An exhibition that opens at Tate Britain this week traces the British art revolutionaries during this decade; iconic works include Michael Craig Martin RA’s Oak Tree (1973), which still has the same dislocating effect as when it was first displayed. A glass of water presented on a small glass shelf is mislabelled as an “oak tree”, revealing – like the many other works in the show – art’s ability to awaken curiosity and to probe meaning.

Luxembourg & Dayan, London, until 16 April
This exhibition of Alberto Giacometti’s sculptural works dating from 1925–1934 – on view on Saville Row, behind the Royal Academy – has been extended until 16th April. It focuses on an early, highly compelling stage of the artist’s career, before he refined the spindly, fragile and elongated figures that became his aesthetic trademark. During the late 1920s and 30s, after he graduated from the Académie de la Grande Chaumière in Paris, Giacometti denounced the traditional realistic approach to sculpture that had been implemented by his teachers. Instead he experimented variously with robust formations that bear a distinctly cubist appearance, Surrealist organic sculptures and minimal geometric abstractions, some of which reflect Giacometti’s early preoccupation with Sumerian and Cycladic art.

Simon Lee Gallery, London, until 6 May
This exhibition will be the first in the UK of Keiji Uematsu’s work. An important Japanese conceptual artist, Keiji Uematsu continually mediates on ephemeral states and processes, such as gravity – “invisible forces” (in the words of the exhibition’s title) that he has explored in performances, drawings, sculptures and photographs over 45 years. Uematsu’s graduation in 1969 from the Department of Fine Arts, Kobe University, coincided with a time of violent student protests and political turbulence. Although Uematsu’s early works do not explicitly reference the fraught times in which they were made, a sense of tension permeates as the artist positions his own body in conjunction with objects.

Studio Voltaire, London, 15 April – 5 June
Sharon Hayes’ rebellious spirit has made her art a talking point. Using performance, film and installation, the American artist uses the language of 20th century protest groups to reflect the politically charged atmosphere of New York in the 1990s. In a new commission at London’s Studio Voltaire, Hayes draws on archives in the US and UK that document the gay liberation and feminist movements – expect a large-scale installation and five-channel film that consider the relevance of these issues today as oppression and violence persist.

Ikon Gallery, Birmingham, until 26 June
The impact of minimalist sculptures is dependent on their site-specific context. This is all the more understood when one sees how Dan Flavin’s fluorescent lights illuminate the varied interiors of Birmingham’s Ikon Gallery in a new exhibition. Unlike Tracey Emin RA’s sinuous and expressive neons today, the works at Ikon conform to rigorous geometry, severing personality from the art object. Yet this doesn’t detract from their ability to evoke atmospheric effect as they bathe the gallery spaces in soft-coloured neon light, deviating from the harshness often associated with minimalism.